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The Ultimate Light Modifier Shoot Out and Test

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Softbox-Testing-Results

As someone who has taught off camera lighting for some years now, as well as taught dozens of workshops on the topic – I’ve always heard the same question from photographers who are using off camera lighting for the first time. “What’s the difference between ____ and ____.” When working with off camera lighting, it’s easy to get overwhelmed with the large variety of tools you have available to you. What’s the difference between an octabox and a regular softbox? I’ve often tried to explain these differences, but it’s always best to just show them with light, so I rented out a ton of gear and decided to demonstrate the difference between each light using my friend Trevor as a model.

All of these tests were performed at 2ft, 5ft, and 8ft from the subject. These were taken using a variety of light modifiers available for rental here at Lensrentals.com, as well as from my personal collection of modifiers. Additionally, they were metered and left unedited while being taken in a controlled environment in a studio. All test lighting were also performed using a Profoto B1 lighting unit. Additionally, these were taken at a 45-degree angle, shot directly onto the subject (not feathered). And finally, the light was exposure balanced to the subjects face and adjusted based on the distance to match the exposure – while the exposures aren’t 100% perfect, it was the best that could be done with the given constraints.

Profoto B1 Strobe (Bare)

These photos are taken with the Profoto B1 strobe without the use of a modifier.

BareLighting-thumb

Profoto OCF 24″ Foldable Beauty Dish

Taken using the Profoto OCF 24″ Foldable Beauty Dish.

Profoto2ftOcta-thumb

21″ Beauty Dish

Taken using the Profoto Beauty Dish in White.

ProfotoBD-thumb

XL Umbrella White

Taken using the Profoto XL Umbrella in White. Similar results can be found using the PCB 64″ PLM in Silver.

ProfotoXLUmbrellaWhite-thumb

XL Umbrella Silver

Taken using the Profoto XL Umbrella in Silver. Similar results can be found using the PCB 64″ PLM in Silver.

ProfotoXLUmbrellaSilver-thumb

Large Umbrella White

Taken using the Profoto Large Umbrella in White. Similar results can be found using the PCB Foldable Octabox 47″.

ProfotoLargeUmbrellaWhite-thumb

Medium Umbrella White

Taken using the Profoto Medium Umbrella in White. Similar results can be found using the Westcott 43″ Collapsable Umbrella.

ProfotoMediumUmbrellaWhite-thumb

47″ PCB Octabox Without Front Baffle

PCB47InchOcta-thumb

47″ PCB Octabox With Front Baffle

PCB47InchOctaFront-thumb

PCB Strip Box Without Front Baffle

PCBStripBox-thumb

PCB Strip Box with Front Baffle

PCBStripBoxWFront-thumb

2’x3′ Softbox With Front Baffle

2ftx3ftSoftbox-thumb

Large PCB Softbox (30″x60″)

LargeSoftboxwFront-thumb

Westcott Rapid Box

WestcottRapidBox-thumb

Large Profoto Octabox (5ft)

Taken using the Profoto Large Octabox. Similar results can be found using the PCB Foldable Octabox 47″.

Profoto5ftOcta-thumb

 

As you can see, this test showed me that there is a lot of diversity when it comes to lighting modifiers. Between distance and placement, a single modifier can be very soft or hard lighting. This is due to the correlation of distance from the subject. When the lighting modifier is closer to the subject, it is bigger by their perspective, thus providing a softer light. When the modifier and light begin moving away from the subject, their perspective of the light shrinks, and will provide harder light as a result.

While the test was initially about seeing how the size and shape effects the subjects face, I quickly found myself to be more interested in how it affects the background. Naturally, the smaller the light source, the more controlled the light becomes, and that as the light gets larger, so does the spill from the light. This is where the control aspects of lighting come into play more than anything.

So what did we learn today? Well first, lighting isn’t as complicated as many may have thought. A lot of the lights modifiers had very similar results and weren’t nearly as unique as many would try to claim. However, these were controlled tests shot directly on the subject – obviously feathering and using the modifiers in unique ways will show you where they shine. But if nothing else, hopefully, this has convinced you to give lighting modifiers a try, as this has shown that they’re not as complicated as you thought.

 

Zach Sutton

Lensrentals.com Editor

The (sort of) Great 400mm Lens Shootout!

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I get asked a lot about different telephoto lenses. Is the 400 DO II better than the 400 DO? Which is better, the Tamron 150-600mm or the Sigma 150-600mm? You’ve probably noticed that I don’t answer those questions. The reason is simple. Our optical bench is designed to test lenses up to 2.5kg weight and a maximum of 250mm focal length. Most super telephotos fall outside that range.

Some old picture or me carrying lenses, because the editor counts pictures in the articles but doesn't read the captions.

Some old picture of me carrying lenses, because the editor counts pictures in the articles but doesn’t read the captions. I know it’s an old picture because if we had an area with that much empty space Tyler would have put 6 workstations in there. Note From Editor: I read the captions.

 

But, of course, we’ve spent most of the last 10 years figuring out how to do things we aren’t really supposed to be able to do. The truth is, with some reprogramming (like overwriting the expected focal length in the software), really careful technique (like a long delay for vibration dampening between each measurement after the machine moves), and a few other manipulations, we’ve found we can test most lenses at 400mm with good reproducibility.

Notice I said most. One lens you’ll see missing today is the Nikon 400mm f/2.8 VR II. Now I do expect that Nikon fans will claim a major conspiracy, but the truth is simpler: the first 400mm f/2.8 VR II is the heaviest super telephoto we tried. When we did, I thought there might be a bit of vibration-induced variance in the results so I don’t think they’re valid and don’t want to post them.

Now Swear the Solemn Oath! (Yes, you have to repeat it out loud.)

Animal House, Universal Pictures, 1978

Animal House, Universal Pictures, 1978

I do solemnly swear that I understand the following.

  1. The reason 400mm was chosen is because it seemed like a nice round number, and there are lots of lenses that get there.
  2. A given lens’ results at 400mm aren’t necessarily similar to those at 300 or 600mm.
  3. These tests were performed on a machine that isn’t designed to handle these lenses, and therefore may, or may not, be all that damn accurate.
  4. The MTF graphs are the average of multiple copies, but for many of the lenses, we used 5 copies instead of 10. These were time-consuming.
  5. A lens tested at f/2.8 should have lower MTF than one tested at f/4, etc. So don’t say something stupid about a f/5.6 lens being as good as a f/2.8 lens.

Also, I promise not to ask Roger to repeat the tests at f/8, or 600mm, etc. because I realize the bank’s going to come take his machines away if he doesn’t start doing some stuff that generates revenue soon.

Very good, you are now members of the Delta Tau Chi optical testing fraternity.  You may now read on.

The Canon Supertelephoto Primes

This is the section for both of you who want the absolute best lens at 400mm, and money is not (or at least not much) of an object. If you’re a Nikon shooter, just pretend the Canon 400 f/2.8 MTF curve says “Nikon 400mm f/2.8 VR”, and then skip on down. The 400mm f/2.8 lenses are pretty identical.

Canon 400mm f/2.8 IS II: The Gold Standard

This is optically the best telephoto there is, and all other lenses are measured by how close they can come to this one. It should be the best, it’s very big and breathtakingly expensive.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

The Canon 400mm f/4 DO IS II

A lot of Canon shooters want to know how close they can get if they give up a stop of aperture and get the markedly less expensive and amazingly lighter 400mm DO II. The answer is at f/4, the 400mm DO IS II is basically as good, at least in the center 1/2 of the image where most telephoto subjects rest, as the 400mm f/2.8 IS II is at f/2.8.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

Let me emphasize that this is the DO II. The original isn’t quite as good as you can see below (The DO II is on the right).

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

And while we’re answering questions Canon telephoto shooters ask all the time, let’s compare the 400mm DO IS II to the Canon 300mm f/2.8 IS II with a 1.4x Mk III teleconverter since these are both f/4, of similar size, and similar cost. The 300mm + 1.4X combination, is, of course, 420mm so it is a bit longer range.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

As you can see, the 400mm DO IS II is a little bit sharper than the Canon 300mm f/2.8L IS II with TC combination on the bench. In the real world, though, the 300mm with TC combination offers some other advantages (like being able to be a 300mm f/2.8 when you want) that may be more important than the MTF curves. As an aside, we experimented a fair amount with the 300mm f/2.8 and 1.4x combos. First using the same lens with different converters, then using the same converter with different lenses. The converters don’t vary as much as the lenses, which makes sense; they’re optically much simpler than the 300 f/2.8 lenses.

The CaNikon Supertelephoto Zooms

OK, the vast majority of us aren’t interested in a $10,000 lens that requires a heavy duty tripod to use effectively. That is a specialist’s tool. We are more interested in that zoom or prime lens that can get us to 400mm at a fairly reasonable price. I understand you’re also interested these days in the third-party lenses that do that and we’ll get to those next. But it’s important to look at your brand’s offerings first, so you have that comparison point. (Spoiler alert: If you shoot Canon you’ll probably love the 100-400 IS II; if you shoot Nikon you probably won’t love the 80-400 VR II).

The Canon 100-400mm f/4.5-5.6 IS II

The Canon 100-400mm f/4.5-5.6 IS II is generally considered one of the best telezooms on the market and it’s MTF curves tend to support that idea. Remember, though, with the zooms we’re looking at them at f/5.6 at 400mm. That’s two full stops less aperture than the 400mm f/2.8 we started with. But the Canon is excellent at 400mm as you can see.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

And just because I wanted to know, we tested the old, but excellent Canon 400mm f/5.6 L prime lens, for comparison. Few people shoot it anymore, but there’s a reason it’s remained in production for decades. It’s not quite as good as the 100-400 IS L, but still, an excellent performer considering how old the design is. (In the lab. In the field I’ll take the IS every time).

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

The Nikon 80-400mm f/4.5-5.6 ED AF-S VR

Commonly called the 80-400 VR II, this lens has been the Nikon 400mm zoom for some time now. It’s, well, it’s better up to about 300mm, but it’s just not that good when you stretch it out to 400mm. Not a great performance for a lens that demands a premium price.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

Nikon 200-500mm f/5.6E ED AF-S VR

The newer Nikon telezoom is something of a different beast. It’s a fixed aperture lens and it zooms out to 500mm, so it’s the first lens in this test that can actually go past 400mm. Plus it’s a lot less expensive than the older 80-400mm. I can’t comment on how it performs in the field, but from an MTF standpoint, it outperforms its much more expensive brother at 400mm.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

The Third-Party 150-600mm Zooms

These recent entries in the super telephoto zoom market have changed things quite a bit. The Sigma Contemporary and Tamron lenses both can be had for under $1,000; much cheaper than the brand-name zooms. The Sigma Sport is a different lens, being almost 50% heavier and about twice the price of the other two.

There is one HUGE, IMPORTANT thing I want you to take away from the MTF curves on these lenses. At 400mm the two Sigma lenses are at f/6.3 maximum aperture, the Tamron is at f/5.6. Now I don’t think that half stop is going to affect your shooting significantly, but it probably will have some effect on MTF curves. The Tamron, Canon, and Nikon zooms we tested above are all done at f/5.6 and should each be at least a little better MTF stopped down. And yes, I know you wish I’d tested them all at f/6.3 to even the playing field. But I’ve got paying customers waiting and bills to pay.

Tamron 150-600mm f/5-6.2 Di VC USD

Just in case you missed it, the Tamron testing aperture is f/5.6 at 400mm, so we can directly compare it to the Canon and Nikon telezooms above.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

If you make that comparison, you’ll see why, for quite a while now, I’ve recommended this lens to Nikon shooters instead of the Nikon 80-400mm VR II; its similar in sharpness, far less expensive, and has additional range. But at the same time, I’ve told Canon shooters if they want the sharpest zoom at 400mm, to stick with the Canon 100-400. Obviously, if they want 600mm range, then my suggestions are quite different.

The Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary A1

The Sigma Contemporary is very similar to the Tamron in size, price, and obviously, range.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

You can probably tell the Sigma has a slightly better MTF, but I’ll put them side-by-side below for easier comparison. I suspect that even if we stopped the Tamron down to f/6.3 the Sigma would be slightly better in the lab, but I also doubt the difference is nearly as great as the copy-to-copy variation. In other words, I wouldn’t consider MTF to be a significant factor when deciding between these two lenses. Things like how it handles, focuses, and how well the stabilization works are going to be way more important.

Olaf Optical Testing, 2016

Olaf Optical Testing, 2016

 

A Word About the Sigma 150-600 f5-6.3 DG OS HSM Sport A1

As I’ve mentioned, despite the similar names this is a very different lens than the Sigma Contemporary. One of those differences is weight and size. It’s the second heaviest lens we tested; only the Canon 400mm f/2.8 weighs more. But the Sigma Sport differs in that a lot of its weight is in a very heavy front element that sits at the end of an extending zoom barrel, which for purposes of testing at 400mm is partially extended. When we tested it, slight vibrations interfered with testing enough that we had several bad readings for each lens. For that reason, much as I wanted to compare the Sigma Sport to the Sigma Contemporary, I just don’t have enough faith in the results to make them public.

Summary

I don’t think we really did too much here today except to have some fun and confirm, in numbers, what most people already know. The 400mm f/2.8 lenses, if you can afford one and don’t mind carrying it, are amazing. Canon’s new 400mm f/4 DO IS II is also superb, at least as good as the 300mm f/2.8 IS II with a teleconverter.

Canon’s 100-400 IS II is, from an MTF standpoint, the best zoom at 400mm, but the Nikon 200-500 and both the Sigma and Tamron 150-600s are also really good, far less expensive, and have greater range. The Nikon 80-400 VR II is not quite as good at 400 as the competition.

 

Roger Cicala, Aaron Closz, and Markus Ruthaker

Lensrentals.com

August, 2016

 

 

Geek Note: Some of you may have noticed the two Nikon lenses seem to have astigmatism right in the center, which is, to say the least, unusual. This is one of the things that has more to do with our testing than reality. Remember we test the lenses rotating them so we take 4 slices to get a complete picture of the lens. With these heavy, extending barrel zooms, the barrel tilts a bit with extending, so the center doesn’t quite stay in the center, it’s a few mm off center in some rotations. Here’s a random 80-400 as an example, showing you all 4 quadrants of MTF.

275124_small_Rotation

You can see that the best center is the 45-degree rotation, but at other rotations, the best reading is slightly off-center. We can have a geek argument that maybe we should recenter at each rotation; it would make prettier MTF curves. My thought was nope because the whole purpose of the 4 rotations is to look at the different areas of the lens at the same position, just like it would be in an image. Besides, this is the way we’ve always done it. But let me add that that is NOT the way the manufacturers would do it. They show you a single cut, so, in this case, our 45-degree cut should be closest to the manufacturer’s ideal.

 

 

 

More PhotoGeekery: Finite Conjugate MTF Bench Tests for Macro Lenses

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For the last several years we’ve talked about the fact that lens performance can vary with focusing distance. Our optical bench tests at infinity. Computerized target analysis (Imatest and DxO) tests at close distances. But when the results of target analysis and bench tests differ it’s hard to decide if the difference is because of different testing methods or because lenses actually do perform differently close-up and at a distance.

When I did target analysis testing, I was most uncomfortable about wide-angle lenses. They are being tested at distances under 6 feet and that’s not the distance they’re often used at. With bench testing, I have the opposite discomfort. We were testing macro lenses at infinity, but they are most likely going to be used close up. In both cases, I wondered how much testing distance affected performance.

macro

Random macro image because social media consultants say we should have more pictures since reading is hard.

 

Faced with this dilemma, I did what I usually do; I spent more money and bought a finite conjugate modification for our optical bench. This allows us to test lenses at close focusing distance with the same methods we use to test at infinite focusing distance. So now we can use the same testing method to see how much difference focusing distance makes.

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How to Use Interview Transcripts as an Editing Tool

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I was introduced to the benefits of interview transcription a surprisingly long time after I’d started learning about documentary filmmaking. Tired of introductory-level film classes and spending hours discussing editing theory between screenings of Koyaanisqatsi, I decided to take a Journalism 101 course in the hope of gaining some actual, practical knowledge. The first thing I learned, and still probably the most helpful advice I’ve ever received about doc work, was to transcribe every interview, no matter how short or seemingly inconsequential. You’re probably already familiar with this process if you’ve ever produced non-fiction of any kind, but if not, here’s the gist of it: You create a written record of your taped interviews by typing out every question and response so you can refer to them later. It’s a pretty simple task and one that’s so mind-numbing that it’s typically delegated to interns, or outsourced to online services at pennies per word. But it’s an invaluable tool that will, without question, make you a better editor. I’ve been at it for a while now (without interns), adjusting my workflow whenever I find a technique or piece of technology that makes things easier. I’m not saying this is the be-all end-all best way to transcribe your interviews. It’s just the way I do it right now. Hopefully, especially if you’re just starting to figure out the way you like to work, there’s an idea or two here that you might find helpful.

Workflow

The absolute most important thing to my workflow, regarding both transcription and editing overall, is that every clip I shoot for a project has a different filename. Personally, I stick with the camera’s clip naming system from beginning to end, just changing the reel name every time I switch cards. It’s simple enough and pretty much automatic. For example, the project I’m currently working on was shot on the Arri Amira. I only shot two cards, both on the same day, so everything is relatively straightforward. As you can see, I have my files split up by reel, with the reel number represented in the first four characters of the file name. The first clip on reel one is A001C001_160528_R56S.mov. That’s camera A, reel 001, clip 001, shot on 5/28/16. R56S is the camera ID, which I can use to determine the serial number of the Amira that recorded the clip. Those 20 characters give you pretty much all the information you need. From there, I import all of my footage into Adobe Premiere Pro.

My personal workflow from here on is pretty dependent on having access to Adobe’s Creative Cloud service. If you use Premiere too, then you can follow along step-by-step. If not, though, you may just want to skim the rest. Sincerely, though, and I say this having never received any promotional compensation from Adobe, it’s the best. If you’re reading this as a beginner and still questioning what program to invest in, I can’t recommend Creative Cloud highly enough. On to the specifics:

Once everything is imported safely into Premiere, I use Adobe Media Encoder to export audio-only versions of every clip I want to transcribe. For many people, this will be only the sit-down interviews. Personally, though, I like to have every scene with dialogue of any kind. I use color labels to identify these clips. Just right click the clip, scroll down to “label,” and change it to something noticeably different from the default. I’m a mango man, myself.

Once the dialogue clips are labeled, just select them all (or do it in batches, whichever is easier) and hit Command-M to open the export menu. Next, select MP3 from the “Format” dropdown. You can change whatever settings you like here, of course, or even export a different audio codec, but I’ve always been happy with the defaults, and most programs you’ll use to transcribe will work with MP3 files. The blue “Queue” button will send everything to Media Encoder so you can continue editing in Premiere while the clips are processed.

Unless you adjust the file name setting in Media Encoder, the resulting files should have the same name as your video clips, but with a different file extension, A001C001_160528_R56S.mp3, for example. This will help keep it clear which audio files and transcript text files are associated with each clip. The next step is to open them in whichever application you’d like to use to transcribe. Personally, I like Express Scribe for this. It’s free, easy to use, and available on multiple platforms, which is helpful. I do all my Premiere work on an impossible-to-move iMac with a connected working drive and RAID backup, so it’s nice to be able to put Express Scribe on a laptop or something, transfer the tiny MP3 files over, go to a coffee shop (or beer shop) and still be somewhat productive. If you find another application that fits your needs better, though, go for it. This part of the process is just generating text by whatever means you like best.

Whichever application or device you choose, this is the time-consuming part. Just hit play and type away using start/stop hotkeys and variable playback speed to eventually get to the point where you never have to stop typing. You’ll want to identify speakers, including the interviewer, in the transcript. That’ll make it much easier later on when we connect transcripts back to clips. You may also want to timestamp the transcript, depending on the length of your clips. I typically keep my clips short by quickly starting and stopping recording during quiet points in interviews, though, so I usually skip it. Make the transcript file name the same as the name of the clip that you’re transcribing, and the following steps should be quick and straightforward.

Here’s where having access to Creative Cloud actually becomes an essential part of my work: the next step is copy/pasting the transcribed text into a little-used Adobe application called Story. Story is Adobe’s solution for scriptwriting, production scheduling, and report generating. I don’t often have use for many of those features, so I didn’t use it much myself until I figured out how helpful it could be for organizing transcribed interviews. You start by creating a new project. Call it whatever you want. Mine, for example, is 1606 because it’s my sixth video project of the year 2016. I keep all my projects organized with that number system, but if you’re more creative than me and have an actual name for the thing you’re working on, have at it. Next, create a new script within the project using the “Film Script” template. Call it something like “Interview Transcripts-Project Name,” or whatever floats your boat.

Adobe Story helpfully formats your script for you by automatically recognizing scene headings and character names. We’ll use this feature to our advantage by replacing standard scene headings, such as EXT. PARK – DAY, with clip names. In my script, the first scene, my first clip with recorded dialogue, is A001C011_160528_R56S. The next scene is A001C012_160528_R56S, and so on. Every clip with transcribed dialogue has a corresponding scene in my Adobe Story script.

My main reason for choosing Premiere over some of the other NLE options out there is how seamlessly it works with Adobe’s other applications. Story is no exception. Once my clips are transcribed and copy/pasted into my Story script, I can open Premiere and import the transcribed “scenes” directly into the metadata of the video clips in my Premiere project. Just switch to the “Metalogging” workspace in Premiere, open the Adobe Story window, load your script, and drag and drop the script for each “scene” onto its corresponding clip. For some reason, this only works in Icon View. The transcribed dialogue is now part of the clip’s metadata and is visible directly in Premiere, which means I can view it while editing without having to open another application or refer to a printed transcript. I can also send any or all of my video clips to a colleague or client without having to worry about also finding and sending transcript files. It’s part of the actual .mov file now, so the transcript goes wherever the video goes and is accessible as long as the application the other person is using can recognize the metadata.

Uses

This may seem like a lot of work to go through, and honestly, it is, but once you consider how fundamentally this improves the editing process, I think it’s well worth it. Obviously, it allows me to print out and read all my interviews, which is undeniably helpful. Now that I work this way I do just as much editing with a highlighter and pen as I do with my computer. But it’s also handy in smaller ways that present themselves on a case-by-case basis. Story can generate “reports” on different parameters that make it really easy to identify and organize information in your script. You can separate out every piece of dialogue spoken by a particular interviewee, for example. There’s also a “find,” function, just like in Microsoft word. So, if you want to identify every clip in which a particular subject or person is mentioned, it’s just a matter of typing it into the script rather than having to scrub through every single interview. Overall I’d say that it saves way more time than it costs.

Finally, and more broadly, it’s really opened up when, where, and how I’m able to edit. Adobe makes a Story app for tablets and phones, and it’s available online through a web portal. Every script syncs automatically, so I have access to text versions of my most relevant video clips everywhere I go. Sure, not every documentary project is dialogue-focused, but the vast majority are. Thinking of the work as text and working with it that way means that I can still edit on a layover, review dialogue at the DMV, organize a rough cut with index cards on my kitchen table, or work from bed, which is really all any of this is about. And, again, it’s not dependent on using Creative Cloud. With a few workarounds you could accomplish pretty much the same thing with Final Cut and just about any word processing program. If you’re not a meticulous transcriber already, try it on your next documentary project, and I guarantee it’ll be worth the effort.

If you have any questions or want to share some of your own transcription techniques, feel free to comment.

 

Ryan Hill

LensRentals.com Video Technician

The Zeiss FE Batis 25mm f/2.8 & Loxia 35mm f/2 Lens MTF Charts

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For quite a while now, some you have asked where the MTF results were for the Zeiss Batis and Loxia lenses, and my answer has been not done yet. There were a lot of reasons for that. Chief among these was the lenses are so popular that we can’t get as many as we want and keep them in stock long enough test them. There were also the issues we had modifying our optical bench for testing lenses with an electromagnetic focus for the Batis lenses.

So this arrives pretty late, way after most of you have made whatever purchasing decisions you are going to make regarding these lenses. But better late than never. With that in mind, though, I’m going to post all of our Batis and Loxia results in one place (here) just like we did in summarizing the Sony FE lenses so that it can serve as a reference.

One thing I will mention, because I think it acts as a good example. Unlike most manufacturers, Zeiss publishes measured MTF curves with their lenses, not computer simulations. When you ask me why my results are different from ones released by Canon or Nikon, I quickly say mine are real; theirs are idealized computer simulations.

When you ask me why my results are different from Zeiss’ results, the answer is that they are different measurement techniques. Some will have to do with various machines; Zeiss uses their K-8 and K-9 machines, we use a Trioptics Imagemaster vertical MTF bench. The light source is slightly different, for example. The Imagemaster uses a photopic light; Zeiss uses (I believe) a broader spectrum source. It may also have to do with the number of points measured, the number of samples tested, and a host of other things.

For example, we measure each lens at four different rotations, taking cuts from side-to-side, top-to-bottom, and from each diagonal, so each lens is measured at 84 points. The main reason we measure this way is that we’ve written software to give us an easy way to compare lenses to see how they differ.

OlafOpticalTesting, 2016

OlafOpticalTesting, 2016

That may be a very different measuring technique from what Zeiss uses. Other differences are going to be our mount, which cuts the 20mm edges in some measurements, or the thickness of sensor glass utilized in the test. (I can only obtain optical glass in 1,2,3 or 4mm thicknesses, and the sensor glass is between 2.3 and 2.5mm thick.) This may make a slight difference, and more importantly, the amount of difference varies somewhat depending on the lens in question.

So why bother to publish this data instead of just letting you look at Zeiss’s data? Because Zeiss doesn’t test the other lens brands. If you want to compare MTF between, say, a Loxia and a Sony FE, then these are worthwhile.

MTF Results

Markus has written an excellent new piece of software that lets me put up side-by-side comparisons just by pushing some buttons. Since I want to play with my new toy, I’m putting each Zeiss lens MTF next to a Sony lens of similar focal length. Remember, though, that they are all measured wide open, so don’t look silly and say this f/2.8 lens is sharper than this f/1.4 lens. Because aperture. And, of course, if you want to compare these to other FE mount lenses, the MTF charts are here.

Zeiss Batis 25mm f/2.8

The closest comparison I came up with is the Sony FE 28mm f/2.0. It’s a fair comparison since they’re both f/2.0, although the Sony lens is far less expensive. The Sony does pretty well from a resolution standpoint in the center where it’s as good or perhaps a tiny bit better than the Batis, but away from the center, the Batis shines, maintaining its sharpness well and with little astigmatism.

OlafOpticalTesting, 2016

OlafOpticalTesting, 2016

 

Zeiss Loxia 35mm f/2.0

I chose the Sony 35mm f/2.8 ZA Sonnar as the comparison lens, so remember, of course, that it is being tested at a stop’s smaller aperture. The Loxia would improve stopped down to f/2.8. Even given its disadvantage, though, it’s apparent the Loxia 35 isn’t the fastest horse in Zeiss’s FE mount fleet. It’s an older design so we shouldn’t be too surprised at that. And yes, I know you’re all curious as to how much better the Loxia would be at f/2.8. So am I but time takes time, and I don’t have any right now.

OlafOpticalTesting, 2016

OlafOpticalTesting, 2016

 

Zeiss Loxia 50mm f/2.0

In this test, I gave the Loxia a full stop advantage by choosing the new Sony 50mm f/1.4 ZA as it’s comparison. On the other hand, the Loxia is considerably less expensive. Despite giving up that stop of aperture, the Sony ZA clearly has higher resolution. However, the smooth, fairly astigmatism-free MTF curves of the Loxia suggest it will have a very different ‘look’ that some people will prefer.

OlafOpticalTesting, 2016

OlafOpticalTesting, 2016

 

Zeiss Batis 85mm f/1.8

The comparison here is with the Sony 85mm f/1.4 GM lens, which is more expensive, but gives up some aperture. Even considering the aperture difference, the 85mm Batis puts in a most impressive performance. Excellent resolution and very flat curves across the field. It’s not an inexpensive lens, by any means, but its performance is most impressive.

 

OlafOpticalTesting, 2016

OlafOpticalTesting, 2016

 

Conclusion

I haven’t gone into great detail about this set of lenses for one fairly obvious reason: they’ve been out quite a while and photographers who love them love the look of them and don’t seem anxious about what the MTF is like. I think this does show, to some extent, why the Loxia Biogon 35mm f/2.0 isn’t as popular as the other lenses, perhaps, but that’s about the most significant thing I see here.

I know some of you are asking where the results for the 21mm and 18mm Batis are, and the answer is ‘not done yet.’ I’ve made a solemn oath not to post data like this until we’ve finished ten copy sets, and those are still so popular that we haven’t finished testing yet, we can’t keep them in stock long enough. Stay thirsty, my friends (and patient).

Roger Cicala, Aaron Closz, and Markus Ruthacker

Lensrentals.com

August, 2016