I’m never one to worry much about lens dust. I’ve written about why you shouldn’t worry about some dust in your lens. But the color bombs they throw out at Color Runs are different. In the last month we’ve had over 20 lenses and several cameras nearly ruined by these things. For what it’s worth, all of the renters tell us they really weren’t near any of the major ‘color bombs.’

Here’s a few pictures from a brand new lens that returned after its first rental — at a Color Run. These pictures are, of course, after the lens was cleaned externally. All of that dust is inside the front and rear elements.

Now a few dust specs rarely cause problems, but this kind of dust affects light transmission and contrast, as well as causing fascinating flare (in pretty colors). The color dust is very fine, tiny specs, made to stick on people as the run by (I’m still trying to figure out why someone thought this was a good idea).  Because of this, the lenses’ weather sealing, front filters, etc. don’t even slow this stuff down. It’s throughout the entire lens stuck on every element, on the gears and helicoids, and in the mirror box of the camera too. And yes, that includes pro-level lenses on pro-level cameras, all of which are supposedly weather sealed. As an added bonus, it doesn’t blow out like regular dust. It must be wiped off.

Here’s a look at the inner rim after the front element was removed.

Here’s the front of group 2, nice and deep inside the lens (excuse the lights, this is a quick post just using worklights).

And here’s one of a dozen Q tips I used to clean out around the focusing gears and helicoids. Remember, this was a brand new lens only used for this one shoot.

The end result for this lens was complete disassembly and cleaning. This was a fairly lucky one – it’s a lens that we can disassemble and clean without requiring factory readjustment. For a lot of lenses that’s not an option.

A number of lenses, including Canon L’s and Nikon Pro lenses had to go to the factory, and at least one has been given the “financially not feasable to repair” sticker. Your guess is as good as mine as to whether they cover it under warranty or not.

You know what I’d probably find more interesting than the photos of what the insides of lenses look like after this? What the inside of the runner’s lungs look like. All my medical training leaves me curious about that kind of thing.

Addendum – here’s a bonus picture. A Sigma 8-16mm with the barrels removed so you can see how pervasive the Fun Run dust was throughout the entire lens. The dust around the mount side of the lens is so thick that it’s blocking the AF motor from working properly and it’s so caked into the lubricant that the helicoids don’t zoom normally. This will have to be completely disassembled and cleaned piece by piece.

Roger Cicala

Lensrentals.com

May 2013

BTW – Because I’ve already been asked: this won’t be covered by the rental damage waiver going forward – it’s considered negligent use of equipment just like when salt spray soaks the camera on the beach.

When our techs started complaining that D600s were all coming back from their first rental with a lot more dust (despite being freshly cleaned before leaving) we didn’t pay much attention to that either. We all remember the oil / dust issues the D3x and D3s had. Those mostly cleared up after a few cleanings.

The dust kept reappearing with every rental, and more impressively – it was generally in the same location (upper left 1/3 of the image). That did get our attention, so we started looking into the matter a bit. We kept dust pictures for 20 consecutive D600s returning from rental and saw the problem was very real.

In general, about 1 out of 4 cameras requires sensor cleaning after a rental. All 20 of the D600s did.

Here are a couple of typical examples (f/16 blank wall photos, contrast and exposure increased). I would point out that these are downsized to 800-pixel wide images. What is barely visible dust on this is quite obvious on a full-size image. The large specs on this are quite huge at full size.

It’s probably pretty apparent that the dust is mostly on the left side of the image. I took all 20 images and layered them onto one in Photoshop, using ‘darken if’ to show the pattern of dust from 20 cameras.

Again, with these downsized images, only the really large dust specs are showing up, but then, those are the ones most likely to show up in a photo. I would also add these almost all seem to be dust specs, not oil, since most of them can be blown off or stamped off using a Dust-Aid. They don’t require wet cleaning to remove as oil spots do.

There are, however, a number of comments from experienced photographers that are having oil spots on D600s. I’m not certain if they’re seeing the same, or a different phenomenon.

We aren’t absolutely certain about the cause, but when we have to look at the sensors for all this cleaning one thing is quite apparent. The D600′s shutter curtain opening seems a bit larger than the other Nikon cameras with a bit of a gap around the shutter curtain. It may well be the shutter movement is pulling dust onto the sensor.

The real question is: Will the dust eventually stop accumulating on the sensor? I think probably so. There’s some dust inside the camera that is getting blown out during early use through the shutter opening. But that’s just an educated guess; only time will tell.

For now, though, if you rent a D600 we suggest looking fairly frequently for dust accumulation. We clean each one before it leaves, but given the amount of dust they return with it’s fairly obvious there could be dust dots on some of your shots if you stop down to f/8 or more.

NOTE: I know someone will want to know. All of these cameras were from SN 300xxxx or 301xxxx. We have another 40 D600s but since they, too, are from these SN runs I don’t plan any further comparisons. We’ll check again when we get higher SNs.

Roger Cicala, sensor images courtesy Adam Remsen and Scott Rambin

Lensrentals.com

October 2012

What Is This?

We have a unique opportunity: We own a very large number of lenses subjected to rather harsh conditions. They get tossed around during shipping, and sometimes the user isn’t as careful with them as you would be with your own lenses. Basically, we have a laboratory set up to stress test camera equipment and we share those results with you.

Our numbers reflect heavy and hard use. Your personal lenses shouldn’t fail nearly as often; they aren’t subjected to rental conditions. But since all of our lenses are subject to roughly the same number of rentals per year, it does provide some comparison about how fragile various lenses are compared to other lenses.

It’s not completely scientific, but it’s a bit more useful than 10 posts on a forum going back and forth between “never had a problem with it” and “mine sucked.”

This list is not a comment about how good a lens is. It’s simply data about how often it breaks under harsh conditions. Some of my favorite lenses are on this list.

What’s New This Year?

A lot, actually. First of all I’m doing a mid-year report. We’ve got twice as many items as we did last year, so half a year’s data is equal to all of the 2011 data we collected.

In the past we’ve looked at our data as repairs per number of copies stocked over time. With better data now, we’re going to present it as the number of rental weeks per failure. That should level the playing field a bit more since nothing stops working while it’s sitting on a shelf. It also may be more appropriate since these items are used so heavily.

For example, if we have 10 copies of a lens, each copy has been rented for 10 weeks, and we’ve had one repair, that lens averages 100 rental weeks per failure.

Lens age is a bit of a variable. Our average item is less than a year old, and none are two years old. But if an item has been released in the last 8 or 9 months, all the copies are new and repairs may seem falsely low. (If it shows up when all are new, well, that’s bad.) When an item is discontinued we still stock it for a year, so all of the copies are older. (This year the Canon 24-70 is the one example.)

Additionally, we now have a 3-person repair department and do about 50% of our repairs in-house. That gives us better information on what’s going wrong. It’s much better than the “internal parts replaced and calibrated” report that we get from some service centers. For some of the lenses we can show you what the weak point actually is.

We’ve also computerized tracking for all of the repairs we’ve sent in to various service centers. This lets us track things like cost, turnaround time, repairs requiring return trips to the service center, etc. There are major differences between brands in how they approach repairs and service. I think that’s important enough to write about.

Equipment Failure Rates

What do the numbers mean?

It is an annualized repair rate of the period from January 1 through July 1, 2012. A physically damaged lens (by our observation or customer report) does not count as a failure for this list. If it’s obviously been dropped, soaked, or otherwise damaged we don’t consider it a failure. For example, if a filter ring is dented, a front element scratched, or a distance window cracked it is not a failure.

There is one less Canon 50mm f/1.0 in the world this year.

It is probable that some lenses included in these numbers actually were damaged, but there was no overt evidence that it was so. We do not accept the factory service center’s word that the failure was “secondary to shock damage,” because a number of brand new, fresh-out-of-the-box lenses that we’ve sent back for repair came back with “shock damage” as the problem.

We make no comment at all on lenses that we have less than 9 copies of (we don’t think that’s particularly useful, it’s too small of a number) or that have been in stock less than 3 months unless something spectacular is going on (there are a couple of those this time).

Limitations and Disclaimers

Now, for those of you who want to reach conclusions from the data, please note the following: the average rental weeks per failure for all lenses and cameras is just over 300 . Everything fails eventually, but that means most items takes a long time to do it.

To determine failure rates with actual statistical significance we’d need at least 400 copies of each lens. We don’t have that many (although we’re getting close on some of them) so take this data for what it is meant to be: something better than a thread telling you about 6 individuals’ lenses; but not, by any means, an infallible fact. Still, it’s better than anything else currently available that I know of.

Depending upon the lens in question we have 10 to 200+ copies. It’s obviously more meaningful when we see 20 failures in a lens we have 200 copies, than when 2 of our 20 copies failed on another lens.

I want you to get an idea of the sample size we’re dealing with, but I can’t put an exact number of copies we because it varies over time. As an example, we had 69 copies of one lens in February but 128 copies of the same lens in June. What I’ll do is use the following descriptions of the sample size: Very large – always over 150 copies in stock; Large – always over 90 copies; Moderate – always over 40 copies; Small – always between 10 and 39 copies. If we see a strong tendency in a very large sample size, it’s very likely to be a real finding. In a small sample size it could very well be random variation.

We’ll look a little further into those by telling you what it was that went wrong. If 4 different things go wrong in 4 different lenses out of 50 in stock, it’s likely to be random. If all 4 have exactly the same problem, it’s more likely there is a weakness in the lens.

The following lenses or cameras we carry were NOT evaluated because we have less than 10 copies or they were in stock less than 3 months.

• Canon: 180 f/3.5 L; 24mm f/2.8; 24mm f/2.8 IS; 28mm f/2.8 IS; 40mm f/2.8; MPE-65 Macro
• Nikon: 14mm f/2.8; 16-85mm VR; 17-35 f/2.8; 20mm f/2.8; 35 f/2D; 85mm f/3.5DX; 105 f/2 DC; 55-200 Dx
• Sony: all Alpha prime lenses; NEX 18-200 OSS; 55-210;
• Tamron: 90mm f/2.8 Di, 180 f/3.5
• Sigma: 20 f/1.8; 70mm f/2.8 Macro; 105mm macro; 180 f/2.8 OS; 300-80mm
• Rokinon: 8mm fisheye
• Panasonic: All cameras except GH2, 45-175mm lens, 100-300 lens
• Olympus m4/3: 75mm f/1.8; 14-42 II
• All Leica, Voigtlander, Pentax, Fuji, and Schneider lenses

If we carry the lens and it isn’t listed above or below, then it’s weeks per failure was greater than 155 weeks (97.5% of the items we carry had a time until failure of greater than 155 weeks).

Finally, the usual ‘don’t read this and lose your mind‘ call goes out: These are heavily used, frequently shipped lenses. A given lens would have a far lower repair rate owned by someone who uses it on weekends, takes good care of it, and doesn’t ship it around the country.

Lenses with High Failure Rates

Lens	Avg. Weeks Per Failure	Sample Size	Common Problems
Sigma 120-300 f/2.8 OS	13	Small	Cam rails (4), focusing barrel, OS
Sigma 50-500 OS	43	Moderate	HSM Motor (4), OS unit (3)
Nikon 70-200 f/2.8 VR II	53	Large	Tripod foot bent (8); AF adjustment (5), resolution (5)
Nikon D800	55	Large	Battery door (6), electronics (3)
Tokina 16-28 f/2.8	57	Small	AF/MF clutch (3 of 3)
Nikon 16-35 f/4 VR	58	Small	Resolution (3 of 3)
Canon 24-70 f/2.8	65	Very Large	Resolution (26); Helicoid collar (19)
Sony 70-200 f/2.8 G SSM	71	Small	USM motor (3 of 3)
Canon 70-200 f/2.8 IS II	83	Very Large	IS assembly (11), Optical adjustment (10); Zoom jam (10); Barrel assembly (7)
Nikon D700	109	Moderate	Bent CF pins (4); Grip peeling (4); PCB (2)
Canon 35mm f/1.4	110	Large	Resolution (18); USM motor (3)
Nikon 105 VR f2.8 Micro	118	Small	VR (2), AF encoder (1), diaphragm (1)
Canon 100-400 IS L	126	Large	MF ring (10). IS (5), AF motor (4)
Tokina 11-16 f/.28	147	Large	focus jam (6); AF/MF clutch (6); loose screw (3)
Canon 5D Mk III	155	Large	CF pins (8), electronics (3)

A Few Observations

Several lenses on the list are ones that we have relatively few copies of: the Sony 70-200 f/2.8; Tokina 16-28 f/2.8; Nikon 16-35 f/4 VR; and Nikon 105 f/2.8 VR. Obviously, just one repair less and they would have ranked much lower or been off the list altogether.

I still believe the Sony 70-200 f/2.8 really does have a high failure rate for a couple of reasons. First, it was also on last year’s list. Also, two other Sony zooms were all just one repair away from making the list this year (24-70 f/2.8 and 70-400) and did make it last year. Plus all of the Sony 70-200 f/2.8 repairs were for the same issue: USM motors.

All of the Tokina 16-28 f/2.8 lenses had the same problem (AF/MF clutch), which is also a chronic problem on the similarly designed Tokina 11-16 f/2.8. Because they’re all failing for the same reason, we think it’s probably a real thing.

The Nikon 105 VR, though, seems to be more of a random event. It’s never been a problem lens and the repairs were for different things.

I think the other trend that’s very obvious is that large, f/2.8 zoom lenses are likely to have issues. Sony, Canon, and Nikon 70-200 f/2.8 lenses all made the list. The Canon 100-400 is there, too, while the Nikon 80-400 and Canon 28-300 barely missed (and usually make the list). The Sigma 50-500 OS and 120-300 OS are on it, too, with the Sigma 70-200 f/2.8 OS barely missing (in a small sample size of 20 copies).

Each seems to have its own issues. The Canon 70-200 IS II has problems with the nylon reverse gears in the zoom ring and its IS unit. The 100-400 with its outer focusing barrel and notorious smooth-tighten ring. The Sigmas have HSM motor problems, OS issues, and barrel/cam issues. The plate for Nikon’s tripod foot is too thin and bends frequently, and the AF system is a bit finicky. The takeaway message is these are among the most complex lenses made today and the complexity shows in higher repair rates.

If you noticed, Sigma released a new version of the 120-300 f/2.8 OS just over a year after the original version. The optical diagram is exactly the same but I suspect we’ll see some more robust internal components in the new version. They’ve also announced new quality control measures at their manufacturing plant. Given the improvements Sigma has made in their repair service, I suspect they’re serious about improving quality.

Confirmation is Always Good

I’m always happier when I can find a logical explanation for the numbers. The Tokina lenses are a good example. They seem to have trouble with the AF-MF clutch system (if you haven’t shot with one, instead of an electrical switch or full-time manual focus, you move the focus ring forward or backward to engage manual focus). If we pull the rubber off of the focus ring, it becomes apparent the clutch is really two barrels held together by tape.

Tokina 11-16 f/2.8 with focusing rubber removed.

The lower (mount side) barrel pulls drops down once the tape is removed, showing the mechanical clutch. The teeth on the upper side engage the small collared screws in the internal focusing ring to manually focus when the clutch is pulled back to manually focus, disengage when it’s pushed forward.

Tokina 11-16 f/2.8, focus barrel separated

A lot of grit and dirt gets in there (probably from inside the lens) and sticks because there is lubricant on the teeth. The brass collars and screws break. So it makes sense that a heavily used lens, like a rental lens, might develop problems from wear-and-tear around the clutch.

I’ve written a couple of entire posts on why the original Canon 24-70 f/2.8 tends to have problems, and as I mentioned earlier, our fleet has gotten older since we haven’t been able to buy new copies since Spring.

With the Nikon 70-200 VRII, the tripod foot bends so often that the 8 we listed are probably lower than reality. Back when Nikon sold parts we kept spares and any tech would replace it, all you have to do is remove 4 screws and put the new plate in. Now, unfortunately, it takes a trip back to Nikon.

Similarly the Canon 70-200 fails for a couple of different reasons, but jammed zoom rings are common and caused by a tooth breaking on the nylon ‘reversing’ gear under the zoom ring. this is a good system – it was used in the Non IS and IS Mk I lenses – but it seems to have some problems with the Mk II. Whether that’s a bad batch of gears or that there’s more resistance in turning the new lens I have no clue. Either way I expect it will be fixed soon.

Three nylon reverse gears support the Canon 70-200 IS II zoom ring.

 A Word About Cameras

This go around, the Nikon D700 is the only camera to really make the list. That was simply because of peeling grip problems, similar to what the Canon 60D had last year. But almost every camera body from every manufacturer barely missed — all had repair rates of right around 10%.

More notable, to me at least, is that we’ve already had almost 10% of our Canon 5D III and Nikon D800s repaired, despite having them in stock only a few months. I said we usually don’t put things on the list that we’ve had less than 6 months, but this is so noticeable it deserves mention. Once again, early adopters seem to be doing some beta testing.

I should mention, these aren’t ‘small number flukes’; we have a lot of these cameras. I should also mention that I’m not including ‘left side AF issues’ in the D800s required repair — we don’t have hard numbers on that yet. These were all for other things. Mostly a battery door that seems to break off if you look at it hard. I suspect either weak plastic or too thin of a pin on the door design are the likely culprits. That wouldn’t have been a big deal if you could buy replacement doors, but with Nikon’s new policy you have to send the camera in for factory service.

With 5D Mk IIIs, CF pins are bending at an amazing rate. With the latter, I suspect the combination of a CF slot and and SD slot (rather than 2 CF slots) allows CF cards to wiggle a bit more during insertion, so the card slots might not line up with the pins properly. I don’t know that there will be an easy fix for this, but be gentle putting those CF cards in your 5D III.

The CF pins inside the camera are long and fragile. If the card isn't lined up exactly they'll be bent or broken.

Factory Service Center, Uhm, Service

I care about this a more than most of you, probably. I send things in for repair every single day while many of you have never sent anything in for repair. But someday you will, trust me on that.

Depending upon which brand you buy, your repair experience, should you ever need it, could be great or awful. I’m personally convinced certain manufacturers are going to some lengths to make repairs a positive customer service experience, other companies are certain that internet fanboy noise will drown out the individual complaints about their horrible service.

First, let me emphasize this is USA only data; things are very different in different countries (particularly for Nikon). Second, other than a corporate account with Canon (in exchange for a large annual fee, we get to pay our bill once a month and get a 30% discount on repair prices) we send everything in just like you. When figuring repair prices for comparison purposes I’ve removed the discount and used Canon’s list prices, so all of the prices and turnaround times are the same as they would be for you. Actually, if you have NPS or CPS you get a bit faster service and lower cost than we do.

The table below shows the average (mean) turnaround time in days and average cost of repairs for each factory service center. Days are the # of days it was at the repair center; shipping does not count. Average cost is a rather blunt tool, but since most service centers use a three or four step, flat-rate repair fee schedule, it has some meaning.

We have no cost figures for Voigtlander or Rokinon because we haven’t managed to get anything back from repair; nor from Tamron because they did not charge us for the few repairs we sent.

For the Nikon fanboys who tell me regularly ‘it’s just because they’re overwhelmed with the D800 problem.’ That’s true, but the number above is the average for the whole year. Repair turnaround was slow last year (18 days or so), got slower before the D800 was even released (25 days), and has crept up steadily since then. It’s been well over 30 days mean turnaround time for the last couple of months. So the number shown in the table is better than current reality.

Also I should point out that current Nikon repair costs are higher than the table suggests. First, I dropped an $1,800 D800 sensor replacement and $1,300 D3x sensor replacement because they were such outliers. I also used prices from the entire year — Nikon raised prices significantly in early April, just after they announced they weren’t selling parts to third-party repair centers anymore (color me paranoid if you like). In the last 3 months Nikon repair prices were significantly higher than the table shows.

Just for curiosity, I compared same-item repair costs for Nikon and Canon 24-70s. All Canon 24-70 repairs were either $268 or $370 (non-discounted price) during the entire 6-month period. All Nikon repairs were $539 or $602 from April 1 onwards; they were $310 before April (although there were only two during that period). I don’t have room to list all the replaced items, but they were similar: barrels, collars, helicoid rings.

Nikon, I love the cameras. I love the prices on the cameras. But Nikon USA’s repair and service sucks and is getting worse. And yes, Fanboy, I know they fixed your item for free in 5 days. We had one come back in 5 days, too (although not this year). I also know they have a great 5-year warranty. But how much does that help when you drop it?

Would I change brands or something over it? Of course not. That’s silly. Nikon makes excellent, reliable equipment and most people need a repair maybe once every couple of years. But I certainly am advising newcomers in a different direction, and I’d be a bit hesitant about picking up used Nikon equipment.

Finally, let me give a good word for a couple of the third-party manufacturers. Five years ago I thought Sigma’s factory service was awful and we used only independent service centers for Sigma equipment. Since then they have made clear improvements, with an easy-to-use website and polite, knowledgeable customer service on the phone. We started using them again this year and their turnaround time and prices were excellent.

While we don’t use them often, Tamron even goes a step better: they guarantee they’ll have an item fixed 3 days after they receive it (I’ve confirmed this with Pat Simonetti, Director of Tamron Customer Service). If they can’t fix it in a timely fashion, they supply a refurbished or new replacement. I should also mention that when we’ve reported a problem to Tamron or Zeiss, both make inquiries about it, getting all the information they can and passing it on to manufacturing. It’s a pleasant change from “there is no problem, we never have problems.”

Tokina is absent from the table because we stopped sending anything in to them years ago. If we can’t fix it ourselves, we use an independent service center. They may be much better now, but I have no information either way.

Roger Cicala

Lensrentals.com

September, 2012

We’ve had this happen now with about 10% of our copies so I suspect others have had it happen, too. Or perhaps not – our lenses get shipped everywhere and we all know how carefully boxes get treated during shipping.

Anyway, here’s a photo of the third copy to have what we call “second element syndrome.” As you can see the front group is just fine but the single-element second group has fallen off of its mount behind the front element. Notice the white blob at the 2 o’clock position on the second element? That’s one of three bits of glass glue that hold the element in place. No shims or clamps for this element.

It’s not unheard of for an element to be glued into place rather than held with clip or screw-in rings, but, this is certainly one of the larger glued-in elements we’ve seen. It’s thin and not very heavy compared to the front element (below) so I can understand someone thinking glue might be enough for it.

We’ve only seen it in copies that have been used (and shipped) several times so it may be far less likely to affect your own lens. On the other hand, we haven’t really seen this in any of the other 10,000 odd lenses we own, so it probably is at least a bit of an issue.

If you’re handy and notice it right away, it’s no big thing to remove the front element and glue the second one back in place. But since these are all fairly new you should be covered under warranty. Unless you get the dreaded ‘impact damage’ notification when you send it in. For our copies, impact damage certainly is a reasonable assumption, though. They’ve been shipped after all. In our experience with Tamron repair, they don’t play the impact damage card very often, so I wouldn’t worry.

I suspect Tamron is already aware of the issue and is changing glues or securing the element in some other way going forward. But you early adopters out there might want to keep an eye on your lens and make sure the second element continues to look firmly seated and not loose.

Addendum: I spoke with Tamron, USA who assures me they haven’t seen this problem at all before now. That would seem to indicate that our habit of shipping things all over the country is certainly contributing to the problem.

I was very impressed with their response. Rather than just telling me “there is no problem”, they’ve taken the report very seriously and sent this lens back to Japan for further analysis to make certain there isn’t a problem with the glue used or the way it was applied in this copy. I certainly wish more manufacturers would adopt this “let’s see if we can find an problem” attitude. As an aside, I mentioned I was impressed with how rapidly their repair department got to this lens and was told very clearly that they get to every repair within 3 days. Now that is impressive!!!

Roger Cicala

Lensrentals

August, 2012

Sigma 180 OS on 5DIII jpg

Then we tested several others copies of the lens…

and they all did it. Then we realized the initial intake testing had been done on Canon 5D Mk IIs and when we tested them back on those cameras, they were fine.

That made the answer pretty obvious, and sure enough, if we saved the shot in raw, rather than jpg, the reverse vignetting went away. Below is the raw version of the same shot as above, converted outside the camera rather than saved as the in-camera jpg.

raw version of above image

Obviously there’s an issue with the camera’s automated illumination correction and the Sigma 180 OS f/2.8 Macro.

If you shoot LiveView, you will see the reverse vignetting on the LCD, but if you shoot through the viewfinder you won’t see it. We did a bit of investigation and here’s what we found:

1. The phenomenon shows up on Canon 5D Mk III and 1Dx cameras only. T4i and 7D bodies with firmware upgrade do not do this, nor do any other older cameras we could test.
2. The Sigma 180 OS and Sigma 150 OS macro lenses both show the effect and its identical. No other Sigma lenses that we stock showed the effect, nor did any Tamron or Tokina lenses. Obviously I can’t test what we don’t carry.
3. If you turn off Illumination Correction in the menu the effect goes away. To repeat, though, Illumination Correction in the 7D and T4i–on or off–doesn’t cause the effect.

My first thought was that the Sigma lenses were using a Canon lens ID that required a lot more vignetting correction than this lens really does.

If that were the case though, I would expect the 7D and T4i would apply similar corrections, but they don’t seem to. Maybe one of you guys can figure it out.

Roger Cicala

Lensrentals.com

August 2012

What Is This?

We started doing this several years ago. We have a unique opportunity: we own a very large number of lenses subjected to rather harsh conditions: they get packed in boxes, tossed around by UPS, and sometimes the user isn’t as careful with them as you would be with your own lenses.

Our numbers reflect heavy and hard use. Your personal lenses shouldn’t fail nearly as often; they aren’t subjected to rental conditions. But since all of our lenses are subject to roughly the same number of rentals per year, it does provide some comparison about how fragile various lenses are compared to other lenses. It’s not scientific, but it’s a bit more useful than posts on a forum going back and forth between “never had a problem with it” and “mine sucked.” For those of you interested, I’d also suggest looking at the LensPlay Lens Defect Survey. Again, it’s not scientific, but it has responses from thousands of users, so it is another large series.

This list is not a comment about how good a lens is, it’s about how often it breaks under harsh conditions. Some of my favorite lenses are on this list.

What Is Different This Time?

After our last report we had planned to put the failure rate up on our website. Unfortunately that became way too complex and we had to drop the idea. We did, however, improve our evaluation procedures significantly during 2011. As a result we detected problems we might have missed a year ago. We also faced some shortages in early 2011 that forced us to keep a number of lenses longer than we usually do.

We’ve also (following suggestions made after the last survey) taken some steps to make our number of lenses more specific. Previously if we had 20 copies of the lens during the year, we called it 20 copies. But some of them may only have been around for 8 months, etc. Starting now we take the number of months each copy was in stock, add all the months together, and divide by 12. If we had 40 total copies, but 20 were only in stock 6 months of this year we would consider it 30 rentable copies.

All of these factors:a more accurate but smaller count of the number of copies; some lenses kept longer than 2 years in early 2011; and better detection of problems made the repair numbers higher this year. In the past about 5.5% of our lenses required repair each year. This year 8.25% did.

What do the numbers mean?

It is an annualized repair rate of the period from January 1 through December 31, 2011. The percentage we use is simple—number of lens repairs divided by the average number of copies of that lens stocked as covered above.

A physically damaged lens (by external observation or customer report) does not count as a repair for this list. It is probable that some lenses included in these numbers actually were damaged, but there was no overt evidence that it was so. We do not accept the factory service center’s word that the failure was “secondary to shock damage,” because a number of brand new, fresh-out-of-the-box lenses that we’ve sent back for repair came back with warranty work denied because of “shock damage.”

We make no comment at all on lenses that we have less than 9 copies of (we don’t think that’s particularly useful, it’s too small of a number). All of our lenses are rented with about the same frequency (we have many more copies of popular lenses than of less popular lenses), so there’s not a great difference in the amount of wear-and-tear one lens gets compared to another.

Now, for those of you who want to reach conclusions from the data, please note the following: Our average failure rate for all lenses during 2011 was 8.25%. If the lens is on the list below, we’ve had more than 9 copies and it has a repair rate significantly above the average rate.

The following lenses we carry were NOT evaluated because we have less than 9 copies.

• Canon: 100 f/2; 180 f/3.5 L; 50 f/2.5 macro; 24mm f/2.8; 400 DO; MPE-65 Macro
• Nikon: 14mm f/2.8; 16-85mm VR; 20mm f/2.8; 28mm f/1.4; 35 f/2; 85mm f/3.5DX; 105 f/2 DC
• Sony: all prime lenses
• Tamron: 70-300 VC
• Sigma: 20 f/1.8; 70mm f/2.8 Macro; 4.5mm fisheye; 105mm macro300-800
• All Leica, Voigtlander, Rokinon, Olympus, Panasonic, and Schneider lenses

Lenses with failure rates 50% or  more above average (8.25%)