Hey Ed, long time no see!
Hope you are keeping out of the rough action in Bangkok at the moment, maybe it has settled down? Anyway, was thinking/hoping you were alright on your part of BKK.
When possible it would be nice to see some infinity/cityscape samples with the ZM25.
kosmoskatten wrote:
Hey Ed, long time no see!
Hope you are keeping out of the rough action in Bangkok at the moment, maybe it has settled down? Anyway, was thinking/hoping you were alright on your part of BKK.
When possible it would be nice to see some infinity/cityscape samples with the ZM25.
/ Henrik
Hey Henrik, the problem is far from over and some escalation is expected in the coming few days. Luckily the protests are still limited to a few places.
Thank you very much for your concern Shooting riots is not really my cup of tea, unless I happen to be in the middle of the action by coincidence.
I will definitely try to shoot some cityscapes other than from my balcony
edwardkaraa wrote:
...
The first shot is focused in the center using magnified view then reframed. The second shot is focused by scrolling the magnified frame to the subject position without recomposing. The good news is that this will give perfect sharpness wide open at least at this close range.
I normally focus and recompose, a habit from shooting rangefinders, and also because it's quicker. But I realize that I have to move the magnified frame which takes 2-3 more seconds. This can be negligible or a big issue depending on the subject.
Edward,
Hi Edward.
Isnt that behavior expected with or without perfectly flat or curved focus plane? At least if
1) lens is fast enough/DOF is short(ish)
2) pixelpitch is high enough
Second clause because we check sharpness in 100% magn.
The ZM25 isnt particularly fast but I expect that shot to have been taken from well under a meter and with F/2.8 "perfect" focus DOF would be in the range of just a few cm. With recomposition focus will then fall behind the ears. It always does. With luck and an upside-down U-shaped focus plane it could be within limits.
After a few days with the A7 I've learned to appreciate focus peeking with the EVF more and more. I come from the OVF/fast matte world and for A7 I would not hesitate to use peeking in your example. I would expect to nail eye-lash focus in 2 out of 3 shots like that. And I would typically take 2 or 3 in a situation like that which for me would be faster than focus and then recompose.
Or at least as quick :-)
Just my cents.
Out of curiosity, when you say U-shaped plane, do you mean the "normal" slightly bent plane which resembling an upside-down U - or - a plane where the edges are actually focused slightly away from center?
Isnt that behavior expected with or without perfectly flat or curved focus plane? At least if
1) lens is fast enough/DOF is short(ish)
2) pixelpitch is high enough
Second clause because we check sharpness in 100% magn.
The ZM25 isnt particularly fast but I expect that shot to have been taken from well under a meter and with F/2.8 "perfect" focus DOF would be in the range of just a few cm. With recomposition focus will then fall behind the ears. It always does. With luck and an upside-down U-shaped focus plane it could be within limits.
After a few days with the A7 I've learned to appreciate focus peeking with the EVF more and more. I come from the OVF/fast matte world and for A7 I would not hesitate to use peeking in your example. I would expect to nail eye-lash focus in 2 out of 3 shots like that. And I would typically take 2 or 3 in a situation like that which for me would be faster than focus and then recompose.
Or at least as quick :-)
Just my cents.
Out of curiosity, when you say U-shaped plane, do you mean the "normal" slightly bent plane which resembling an upside-down U - or - a plane where the edges are actually focused slightly away from center?
Of course you raise some very valid points, but I think the focus difference is way too important and smearlike to be attributed to a slight shift in focus plane. I have tried focus/recompose also at several meters away subjects and obtained similar and consistent results.
I have been using this technique on the lower resolution M9 with this lens very successfully so I am pretty sure of my findings.
The shape of the curvature which is induced by the sensor glass is in the form of a U, where the focus plane goes further away from the center to the corners. (the ZM 25 has practically no curvature on the M9). When you focus at infinity, the corners will be focused beyond infinity. To bring the corners into acceptable sharpness, you will have to focus pretty close, which will reduce center sharpness considerably. I believe this is a typical consequence of thick sensor cover and wide angles.
As for peeking, I have tried it already and found the results all over the place. I would get peeking lines on my subject and also on a wall 2 meters behind. I tried lowering the peeking intensity and the sharpness settings but that didn't work. I am currently getting acceptable results without the peeking feature, but when I have the time, I will magnify the view just to be sure.
Well, also the new Voigtländer 50/1.5 asph VM seem to have curvature on the A7r, but with the U shape towards the corners, i.e the corners are sharper than the centre. So strange field curvature seem to happen not only to wides. But I actually like the effect in the photos I have seen!
That is the U shape curvature I'm talking about. In some photos where the subject is centered at a close distance, I'm getting sharp corners several meters behind the focus point.
ceder wrote:
Well, also the new Voigtländer 50/1.5 asph VM seem to have curvature on the A7r, but with the U shape towards the corners, i.e the corners are sharper than the centre. So strange field curvature seem to happen not only to wides. But I actually like the effect in the photos I have seen!
Of course you raise some very valid points, but I think the focus difference is way too important and smearlike to be attributed to a slight shift in focus plane. I have tried focus/recompose also at several meters away subjects and obtained similar and consistent results.
I have been using this technique on the lower resolution M9 with this lens very successfully so I am pretty sure of my findings.
The shape of the curvature which is induced by the sensor glass is in the form of a U, where the focus plane goes further away from the center to the corners. (the ZM 25 has practically no curvature on the M9). When you focus at infinity, the corners will be focused beyond infinity. To bring the corners into acceptable sharpness, you will have to focus pretty close, which will reduce center sharpness considerably. I believe this is a typical consequence of thick sensor cover and wide angles.
As for peeking, I have tried it already and found the results all over the place. I would get peeking lines on my subject and also on a wall 2 meters behind. I tried lowering the peeking intensity and the sharpness settings but that didn't work. I am currently getting acceptable results without the peeking feature, but when I have the time, I will magnify the view just to be sure....Show more →
Right, got you and I dont doubt your findings.
The images you posted arent clickable - or rather - ends up in a 404 Flickr page so I am not able to see what you call smearlike but it sounds bad.
I stopped using focus-recompose years ago when I got the (still) high pixelpitched Canon 7D. Even with the comparatively slow lenses I used at the time showed unacceptable behind-the-ear-focus with recompositions. Of course focus was pixelpeeped, while viewed as an image still much ok.
Actually, that is one key reason moving from AF to MF and then Alt and ending up here :-)
philber wrote:
Charlie, call me ridiculous, but that snow shot does show magenta sides IMHO. If it were mine, I'd CornerFix it. Which doesn't invalidate using the lens of course...
You are never ridiculous
No doubt there's a mild shift there. I have not shot my cornerfix/flat field corrections yet so I could not fix it yet if I had to
I'm afraid our beloved zm18 is not even up to my standards on the A7r: just too much smear
I'll have to wait for a native; but meantime my nFD 20/2.8 is very good
Dustobub wrote:
I'm personally not looking to shoot landscapes at f8 with this lens. I'm looking for a standard-wide walk around for available light street scenes and need to be able to comfortably shoot at f2.8 and f4 without requiring a lot of fixing. I'm hoping the CV 35 1.4 might meet that requirement.
uhoh7, do you have any wide aperture CV 35 1.4 shots that you could share? Thanks.
edwardkaraa wrote:
Playing with the ZM 25 today, I discovered that the normally well behaved "clinical" lens suffers from substantial U shaped field curvature on the A7, even at close distances where the focusing group is actually further away from the sensor.
Since the field curvature is U shaped, focusing with the frame center and recomposing is a big NO as you can see in the below examples.
The first shot is focused in the center using magnified view then reframed. The second shot is focused by scrolling the magnified frame to the subject position without recomposing. The good news is that this will give perfect sharpness wide open at least at this close range.
I normally focus and recompose, a habit from shooting rangefinders, and also because it's quicker. But I realize that I have to move the magnified frame which takes 2-3 more seconds. This can be negligible or a big issue depending on the subject.
Thank you for posting this Edward. I haven't had a chance to play with my ZM25, but you've probably saved me from ending up with poor results.
What Sony need in the menus is a way to change that focus movement mode from allowing you to move it anywhere, to only allowing 3 positions:
1. Centre of the left third of the frame
2. Centre of the frame
3. Centre of the right third of the frame
That would cover me for most shots. So a single left click of the wheel or control assigned to move the focus point would move you to position 1 if you were in the centre already. Likewise a single right click would move you to position 3. It would be miles quicker which is critical when trying to take pics of things that don't sit still.
p.135 #11 · A7/A7r - performance with WA RF lenses
Question for people with the CV35 1.2. Is the lens too front heavy for the a7r? or is it manageable.
In terms of overall weight, its the same as a Leica M with a 35 cron, lux or zm attached. but obviously the leica will be more balanced with any of those lenses.
It is just personal preference but in the first shot that bokeh is exactly what I don't like in bokeh. Also with regard to your question, when you say the 35 asph is not do you mean the cron? I wonder how the 35 lux ASPH non-FLE performs. I would expect since it has such a similar design to the FLE that it would do almost as well, but I don't think I have seen any shots with it. It is considerably cheaper than the FLE and some like its bokeh better.
Dec 05, 2013 at 11:25 PM
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p.135 #14 · A7/A7r - performance with WA RF lenses
BenM wrote:
Thank you for posting this Edward. I haven't had a chance to play with my ZM25, but you've probably saved me from ending up with poor results.
What Sony need in the menus is a way to change that focus movement mode from allowing you to move it anywhere, to only allowing 3 positions:
1. Centre of the left third of the frame
2. Centre of the frame
3. Centre of the right third of the frame
That would cover me for most shots. So a single left click of the wheel or control assigned to move the focus point would move you to position 1 if you were in the centre already. Likewise a single right click would move you to position 3. It would be miles quicker which is critical when trying to take pics of things that don't sit still....Show more →
Please no, I want to be able to move the focus magnification around. I actually really like the system on the OM-D. They have a number of boxes that you can make bigger or smaller (bigger boxes means fewer boxes) and you move between the boxes with a four point arrow. I find it easy to move to the spot without even looking and once you are at the box you want you just turn the focus ring for magnification. It is quick and lets you move anywhere on the screen.
p.135 #15 · A7/A7r - performance with WA RF lenses
Agree your question is good and so is your evaluation of the Leica 35 asph. Is the CV 35mm f 1.4 and the f 1.2 the best of the RF35s out there for the A7?
I think a good question is: at 35mm, besides native and FLE, what 35 is compact and decent out to the edges at f/4-2.8?
p.135 #18 · A7/A7r - performance with WA RF lenses
Lambers, you have some mighty strange magenta color shift in that second shot. Right in the middle of the frame! It must be the thin sensor topping Sony designed to make the centre of the pics sharper!
Not that it will make a huge difference, but both were resized to 24MP... still, look very good, though I do think the frame edges look a touch nervous.
p.135 #20 · A7/A7r - performance with WA RF lenses
rscheffler wrote:
Not that it will make a huge difference, but both were resized to 24MP... still, look very good, though I do think the frame edges look a touch nervous.
I agree with both of you,except I have a quetion for Ron. How does resizing affect corner smear. My hunch is that, once smeared, nothing can resurrect the sharpness. So resizing is not a magic wand to get out of trouble, and thus, the resizing does not affect the validity of the shots as proof of minimal smear. Right or wrong?
