Currently, I may (have to) concentrate a bit more on the subject „videographic“ and therefore some of my thoughts are on what are the best camera settings and what gear can be combined in a useful way. In fact, I own a few good e-mount lenses for APS-C format and that made me search for a quite important answer to the question: „Does it make sense to use APS-C crop mode for video recording?“.
What made me think to use APS-S crop mode for video, beside the fact that I have the few good e-mount lenses for APS-C format on the NEX-7 (SEL 1018 F4 OSS, SEL 16-70 F4 ZA OSS, SEL 20F28)? Mainly this: The Sony alpha 7 (and alpha 99) use „full sensor readout“ and „line skipping“ to record video. Understood? No? Well, that means: The entire sensor is used (full sensor readout) but only a certain number of lines are converted into a 1080p video. Looking at a picture taken in 16:9 with 3360 lines I draw the conclusion that a little more than two third of all lines are binned.
In fact this leads to the assumption that using APS-C crop mode would make a lot sense, because looking a picture take in 16:9 and crop mode with 2208 lines only a little more than 50% of the sensor lines would be skipped. Which would mean, that all those nice APS-C lenses could serve very well on the alpha 7, especially the little tiny pancake SEL 20F2.8, right? WRONG!!! This is where Sony puts a spoke into the wheel, because the algorithm for video recording in APS-C mode does the following. It renders the APS-C picture up to full sensor size to re-apply the line skipping. EPIC FAIL – sorry to say, Sony!
I have tried to document this with the following video snippet – have a look at the cables of the cable-car. Click on „HD“ for better quality, click on „Share“ and „H.264“ to download video: