Samuli Vahonen
Offline
• • • •
Upload & Sell: Off
|
 p.112 #16 · Official: Sony A7 and A7R Fullframe Mirrorless | |
carstenw wrote:
I couldn't find the mirror lockup on the A7, but I did a preliminary test to take a quick, early look if there is something which needs to be looked at closer here.
Setup:
Leica 180/2 at f/4 on Gitzo GT3541XLS tripod, only the thickest leg out, Burzynski Ball Head II (very, very strong, can carry 65kg, or more), RRS lens plate and clamp. Wooden floor (sorry, too cold on the concrete balcony for tests right now), so some vibration is possible (it is late, unlikely anyone is moving, and I was standing still, no cars driving by, no obvious earthquakes, but who knows). Of the crucial shot, I made three of each and looked at the sharpest.
I have not much light here, so I used ISO to vary shutter speed. I went from 2s to 1/125s, no movement anywhere, both with and without electronic first curtain. I am fairly confident, but will repeat with good light. All shots were as sharp as can be expected at the respective ISOs (from 100 to 25600).
Then I repeated everything with Nikkor 300/4 + 1.4TC, set to f/8, only ISO 25600 and 1/15s (often a problematic speed in my experience), and this time, there was a clear difference between the two setups. The shot with electronic first curtain was consistently sharper, not much, but clearly sharper. I think it would probably be possible to see it in 100% view, 50% and 25 %. After that probably not.
This is the A7, so 24MP.
I will repeat another time with more light, but clearly, there is potentially a problem here. 36MP is more sensitive, so with no electronic first curtain, there will be a limit to which shutter speeds and which focal lengths you can reasonable keep sharp....Show more →
Carsten, thanks for the test. If it can be systematically repeated on your extra stable environment, it means that it's real issue in the field conditions in practice, not just in theory. So definitely A7 with electronic 1st curtain for me. Thanks for solving my camera selection issue!
This forum is really great; we have been able to find and solve most of the real issue. This is not the first time and hopefully not the last time. Most reviews in web are useless because done either by fanboys or "I'm camera reviewer but I don't want to say anything negative to get ads to my site and get stuff for free for 'review' purposes"-guys. Only few review sites (e.g. Lloyd) are actually discussing product flaws and making it clear for potential buyers.
I clearly remember when we found out the 5DmkII live view high shutter speed darkening and figured out the wayaround for it (which I don't anymore remember  ) even this forum is supposed to be about alt lenses, not about mainstream cameras. At same time on other places fanboys were claiming it's vignetting etc. obvious BS and killing the discussion.
Samuli
|
