Tag Archives: Lens

Sony 100-400mm F4.5-5.6 OSS GM

The Sony 100-400mm GM is a super telephoto lens for full frame E-mount cameras and currently the longest native zoom lens available for this system. GM is short for G Master, Sony’s premium lens line. So is it just an expensive piece of glass or a masterpiece? Let’s find out if Sony is able to match the expectations.

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Canon EF 200mm f/2.8L II USM

The Canon EF 200mm f/2.8L II USM is an inexpensive telephoto prime lens for full frame cameras. It has been on the market for quite a while, a little over 20 years to be more precise. Can it still convince in terms of optical performance on a modern, high resolution camera? I have tested this lens with the Sigma MC-11 adapter on the Sony A7 III.

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How to check a lens for decentering

There are many things that can be wrong with a photographic lens. Optics require tight manufacturing tolerances in order to produce high resolution images. Copy to copy variation is a serious issue, even (or especially?) nowadays. While most lenses leave the factory in good condition, a non-negligible percentage reaches the market with unacceptable optical flaws. One of the most common issues is decentering.
Since this happend to me a few times already, I decided to write a short article about it. I will first explain what decentering means and then continue with a simple procedure on how to test a lens.

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