APS-C E mount lenses on Alpha 7 and 7r

[joe_hunt1]

<p>I understand that the Alpha 7 will crop the edges of the frame when APS-C E-mount lenses are used, to compensate for the smaller coverage, and will thus output images of lower resolution.<br>

I'm interested to know whether that's quantifiable: whether it's a fixed crop to an APS-C sized sensor size, or if it varies between different APS-C lenses, and what size the output resolution would be for the 24 and 36 mp sensors in each case.<br>

Is it simply proportional to the ratio of the areas of the FF and APS-C size sensors or is it more complicated than that?</p>

[phule]

<p>Neither the A7 nor the A7R require you to turn on cropping for non FE series lenses. You can get the full output and crop the image yourself in post.<br /> http://www.dpreview.com/previews/sony-alpha-7-7r</p>

<blockquote>

<p>The two cameras are perfectly capable of using existing E-mount and A-mount lenses, and you have the choice as to whether the image is cropped. If you choose to crop, the resolution will drop to 15 megapixel on the α7R and 10 megapixel on the α7, and the equivalent focal length will increase by 1.5X. Sony also gives you the option not to crop and use the entire sensor, though this may lead to strong vignetting (and for most lenses, probably will).</p>

</blockquote>

 

[joe_hunt1]

<p>That's what I thought - simply proportional to the sensor areas. It might be possible in some instances to get a somewhat larger than APS-C size frame for some subjects (though not full frame) if the drop-off isn't too sudden.<br>

As I'm shortlisting a NEX 6 at the moment, it could be useful to have some continuity if I later went to a FF Sony A7, or its successor, (especially if the A7's lens range stays restricted and expensive).</p>

[joe_hunt1]

<p>Also, when using APS-C lenses and cropping later to a maximum square format (possibly an appealing thought for some), would make more efficient use of the image circle, increasing the pixel count to about 18 megapixel for the A7R and 12 megapixel for the A7, with a "crop" factor of 1.4x.</p>

[Colin O]

<p>If you go to the following review (in Chinese) and scroll down not quite halfway, you can see the effect of each APS-C E-mount lens mounted on the Alpha 7/7R. I expected the image circle to be just that - a circle. But it seems some focal lengths project an "image (rounded) rectangle"?<br>

<a href="http://www.mobile01.com/newsdetail.php?id=14168">

http://www.mobile01.com/newsdetail.php?id=14168</a></p>

[joe_hunt1]

<p>Yes I see that Colin, with the longer end of the zooms. Could it be something like a rectangular anti-flare baffle built into the APS-C lenses? The good news appears to be that more of the frame format is useable at the longer end of the zooms, also something which should apply, I think, at closer focussing distances. <br>

Looks like a very thorough review - pity my Chinese isn't up to scratch.</p>

[rdm]

<p>Wish Sony had the option of an in camera aspect ratio of 1:1 like Olympus and Panny do so you can see and compose in the EVF</p>

[david_wicks]

<p>There are some pictures and a good explanation on dpreview.com about how the a7 handles the e mount lenses, Depending on a setting selection in the menu system. You can either get a round image that does not cover the whole sensor or the camera can make the smaller image cover the larger sensor. Check dpreview.com</p>