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Category Archives: Lenses and Optics

Setting Up an Optical Testing Station

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There are a lot of right ways to do optical testing. The gold standard is to put the lens on a $150,000 optical bench or run it through a well-equipped Imatest lab. But unless you have an optical bench or Imatest lab handy, that’s not practical. We have to optically test around 400 lenses a [...]

Why You Can’t Optically Test Your Lens with Autofocus

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By far the most common email and PM I get basically says, “I think my lens is optically out of sorts. What do you think?” The second most common is, “So what’s the best way to optically test my lens without a ton of equipment.” Years ago I wrote an overly long post about testing [...]

Tamron 150-600 Telezoom Shootout

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There’s been a lot of interest in the newly released Tamron 150-600mm f/5-6.3 SP Di VC USD lens. (For those wondering what the initials mean, VC means vibration compensation, the others all read ‘marketing drivel’.) But meaningless initials or not, with a price under $1,100, a superior range, and vibration compensation, this lens has created a lot [...]

There Is No Perfect Lens Test, Either

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In my last article, I wrote about the fact that every copy of a given lens has some bit of sample variation. This affects lens reviews, whether lab-based or photography-based, because the copy they tested will be just a bit different from the copy you buy. I suggested, that if you want to get a [...]

There is No Perfect Lens

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The Three Questions I get asked a couple of questions every time I publish a graph showing Imatest results for multiple copies of lenses like the one below. Most people understand that some copy-to-copy variation is inevitable in the manufacturing process. Most are surprised, though, at how large the sample variation seems to be. Heck, [...]