ecarlino Offline Upload & Sell: On
|
p.27 #20 · Sony 85mm 1.4 GM testing thread | |
themartinf wrote:
Hi all,
I just registered for this forum after reading through this thread.
I just recievied my 85 GM today and think I might be able to contribute something here, using it with the A7R II with firmware 3.2:
For me after a short test, the main problem is that the lens does not open up the iris all the way for focussing. This results in very slow focus speed when stopped down, getting worse the less light you have on your subject.
It does not make a difference if you use "Live View Display" "Setting Effect" on or off. The iris in the lens does stay put at the value you choose.
Not only does that affect focus accuracy (ever tried focussing a dslr stopped down? you never know where exactly you focus... ) but makes this lens pretty much useless for working in dim studios with just model lights or at any place which is not in bright light. The viewfinder gain gets turned up all the way making the view laggy and grainy, AF is really bad, slow and loud. It really gets louder the less light reaches the sensor.
Seems this lens is really designed to be shot wide open, but sadly in a pretty odd way.
My 55 and 90 fe lenses don't show this behaviour, the open up the iris all the way to focus, or leavit upon till after focussing, depending on the menu settings.
Or is it me who is too stupid to use this lens which seems to be quite great in all other aspects? Am I missing something? I would hate to take it back to the dealer...
thanks,
martin
...Show more →
Martin -
Firstly, your website is beautiful. I thought my favorite portfolio was going to be all the hot German women, but 'Papa' left me speechless - powerful moments captured by photography at its best.
As far as the 85GM, for reasons Sony hasn't disclosed yet, the GM lenses do not open up to initially acquire focus as has been the case with native FE lenses thus far. It would seem reasonable to speculate focus_shift is their reason, and their choice to only focus at shooting aperture would be a smart one if that is the case. The biggest question I'd have for Sony is whether or not the GM lenses are using PDAF if they are not opening up, or are there certain apertures or ambient light levels where PDAF does work and others that it is not used. For example, "non-GM, native-FE mount" lenses will only use CDAF if the aperture is stopped down beyond f/9 - I wonder if that becomes something like f/4 with the GM lenses? In the end, I'm not as concerned about 'how' it is doing things, rather what it is capable of and what expectations i should have in various situations.
When I am in good light shooting at f/2.8 or faster, it's quite fast at focusing. I never stop down more than f/5.6 - but that would be outdoors (city skylines, cityscapes, landscapes) and it still focuses promptly. The few times that I've been indoors in dimly lit situations, I've noticed it hunt and peck a bit more - but it still gets it (I'd be at f/2.8 or faster).
Last Saturday, I wanted to see how well it could keep up with my son as he played on the playground. The following shots are typical of the results. These were at f/1.7 or f/2 with Eye_AF. I would say that they are not quite as good as someone posing, but they are more than acceptable.
Your studio shooting is very different than these outdoor shots. If the lens has characteristics you prefer, would it be possible to add a few lights to assist the lens in its autofocusing? Also, as noted by others, different settings can help, so experimenting is worthwhile: size of focus, Continuous vs. Single, etc.
eric
http://www.ecarlino.net/share/TJC_LP/TJC_LP_%201.7_1-800%20s_100_85%20mm_2.jpg
http://www.ecarlino.net/share/TJC_LP/TJC_LP_%201.7_1-800%20s_100_85%20mm_1.jpg
http://www.ecarlino.net/share/TJC_LP/TJC_LP_%201.7_1-800%20s_100_85%20mm.jpg
http://www.ecarlino.net/share/TJC_LP/TJC_LP_%201.7_1-640%20s_100_85%20mm.jpg
http://www.ecarlino.net/share/TJC_LP/TJC_LP_%201.7_1-500%20s_100_85%20mm_2.jpg
|