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Archive 2014 · A7r plus Canon 16-35 and 24-70

  
 
Jglaser757
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p.1 #1 · p.1 #1 · A7r plus Canon 16-35 and 24-70


I am so close to pulling the trigger on the A7r but I had a few questions.

I currently own a 5dmk III and quite a few Canon L glass lenses. I only shoot landscapes and want the DR and resolution of the sony.

Will the 16-35 II on the A7r cause vignetting?
Will the 24-70 II on the A7r cause vignetting?









Apr 03, 2014 at 04:50 PM
johnctharp
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p.1 #2 · p.1 #2 · A7r plus Canon 16-35 and 24-70


I'll add a second question- what kind of vignetting are you talking about? Do you mean vignetting more or less in relation to what you'd see on the Canon, or do you mean some form of mechanical vignetting?

Other possible aberrations I understand, but why would there be mechanical vignetting when using a full-frame lens on a full-frame camera, unless there was something seriously wrong with the adapter?



Apr 03, 2014 at 05:01 PM
Jglaser757
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p.1 #3 · p.1 #3 · A7r plus Canon 16-35 and 24-70


johnctharp wrote:
I'll add a second question- what kind of vignetting are you talking about? Do you mean vignetting more or less in relation to what you'd see on the Canon, or do you mean some form of mechanical vignetting?

Other possible aberrations I understand, but why would there be mechanical vignetting when using a full-frame lens on a full-frame camera, unless there was something seriously wrong with the adapter?



Good questions to ask,,For me, i am concerned about mechanical vignetting first and foremost..

My thought was that with the adapter, I might get some vignetting. I do when I use a filter holder.



Apr 03, 2014 at 05:05 PM
mawz
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p.1 #4 · p.1 #4 · A7r plus Canon 16-35 and 24-70


The adapter will only cause vignetting if it's an APS-C adapter (like the earlier Metabones adapters).

Functionally the adapter on an A7 is the same as the mirrorbox on the 5D. It exists solely to put the mount at the right location. The filter holder is in front of the optics and is irrelevant to the discussion (if it causes mechanical vignetting on the 5D, the same will occur on the A7r)



Apr 03, 2014 at 05:13 PM
rosscova
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p.1 #5 · p.1 #5 · A7r plus Canon 16-35 and 24-70


As far as the "mechanical" vignetting of something physically getting in the way of the light (that's what's happening when you put a filter on a very wide angle lens; try a "slim" mounted filter instead), as long as you use an adapter meant for full-frame (the version III metabones for example), you shouldn't have any problems.

As for the "light fall off" vignetting, caused in part by shallow incident angles of light on to the sensor, and creating different levels of fall-off on different sensors based on micro-lenses, among other things. All SLR lenses have relatively long registration distances, which should equate to reasonable incident angles of light onto the sensor (despite some of them being very wide angles like your 16-35). Your adapter moves the lens further away from the sensor, meaning that the lens and sensor sit in the same relative positions as on the SLR bodies those lenses are designed to work with. As far as the "light fall off at the edges" kind of vignetting then, I wouldn't expect any more issues in this respect than would already be present on your DSLR.

The vignetting most people are talking about with these cameras mostly affects lenses with very short registration distances, like M-mount. These lenses were mostly designed to work with film, which accepts light at shallow incident angles much better than a digital sensor, meaning the optical engineers could put the rear lens element much closer to the film plane. This is not a problem with SLR lenses, because engineers had/have to push the lens forwards to avoid the mirror-box. In other words, any SLR lens will face this issue far less than some (particularly wide angle) rangefinder lenses.



Apr 03, 2014 at 05:16 PM





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