p.5 #1 · Official: Voigtlander 15mm f/4.5 III E-mount
GMPhotography wrote:
Yea sending choppy over for Fred to try it side by side with the others. Choppy is a special VC 15III has he had his petals ( hood) cut off by some very rude photographer.
I did several tests this morning with it for Fred and we decided best to have Fred test it against the copies he has. So hopefully he will have some updates later in the week.
My feeling is that your copy is better because you banged it against the wall to remove that hood!
p.5 #5 · Official: Voigtlander 15mm f/4.5 III E-mount
Fred Miranda wrote:
Update:
Guy just sent me some samples showing much better extreme corner performance. I have two CV 15/4.5III lenses here (M-mount and E-mount) and they perform similarly (I can't tell apart). However, it's still possible there are better copies out there.
Next week, he will ship his lens to me (Thanks bud!) so I can compare it side-by-side with mine. I will update the thread with the results.
I can clearly see astigmatism and low contrast towards the edges with my copies. It seems excessive and Guy's examples do not show that at all.
I don't think only astigmatism is the cause. What aperture is this at? If it is f/8, I would be surprised if there should be a large amount of coma left, but the large loss of contrast (see: bushes) is more indicative of coma than astigmatism. Certainly there is some astigmatism, but there is much more than that at play with the lens.
p.5 #7 · Official: Voigtlander 15mm f/4.5 III E-mount
Diffraction also reduces contrast. I didn't think coma played a big role as most of the test images I examined were at f/8.
At first, with other images, I thought it was smear (being a variant of a rangefinder lens) but after placing different objects at the extreme corner area, there is a indication of astigmatism because the sagittal lines seem to be always sharp at infinity. I still think I have not seeing a good copy of this lens.
Brandon Dube wrote:
I don't think only astigmatism is the cause. What aperture is this at? If it is f/8, I would be surprised if there should be a large amount of coma left, but the large loss of contrast (see: bushes) is more indicative of coma than astigmatism. Certainly there is some astigmatism, but there is much more than that at play with the lens.
p.5 #9 · Official: Voigtlander 15mm f/4.5 III E-mount
Easy way to test for astigmatism, if when you focus there is a point where sagittal features are sharp and another where the tangential features are sharp, that is astigmatism.
p.5 #10 · Official: Voigtlander 15mm f/4.5 III E-mount
Brandon Dube wrote:
Easy way to test for astigmatism, if when you focus there is a point where sagittal features are sharp and another where the tangential features are sharp, that is astigmatism.
In theory it's easy but at the extreme edges of an 15mm ultra-wide (18mm to 21.6mm from center) with lower contrast and very strong vignetting it's not. To make it harder, there are very little changes in focus at 12x magnification when slightly moving the CV 15 focusing ring.
But yes, I agree, it should focus on the sagittal or meridional lines if it's indeed astigmatism. Like you wrote, it could also be other aberrations in place. There is moderate LaCA towards the edges with the CV15 even when stopping down.
It would be nice if Voigtlander published MTF graphs for their lenses.
p.5 #11 · Official: Voigtlander 15mm f/4.5 III E-mount
Fred Miranda wrote:
In theory it's easy but at the extreme edges of an 15mm ultra-wide (18mm to 21.6mm from center) with lower contrast and very strong vignetting it's not. To make it harder, there are very little changes in focus at 12x magnification when slightly moving the CV 15 focusing ring.
But yes, I agree, it should focus on the sagittal or meridional lines if it's indeed astigmatism. Like you wrote, it could also be other aberrations in place. There is moderate LaCA towards the edges with the CV15 even when stopping down.
It would be nice if Voigtlander published MTF graphs for their lenses....Show more →
I'm not alone then with difficulties focusing my 15/4.5 on my A7RII!
Unlike many of my other lenses that are very very obvious when peak sharpness is reached (I'm even talking about my 16/3.5 AI fish that clearly has a peak infinity sharpness), the 15/4.5 has a broad range of focus turn that all appear to be pretty close in sharpness in the center of the frame - never really looked in the corners while focusing to make sure they are "optimal".
I'm still interested in the native E mount version just for convenience of having the focal length/aperture in the EXIF.
p.5 #12 · Official: Voigtlander 15mm f/4.5 III E-mount
I would too like having the E version also but I need to find one as good as mine. Lol
jhinkey wrote:
I'm not alone then with difficulties focusing my 15/4.5 on my A7RII!
Unlike many of my other lenses that are very very obvious when peak sharpness is reached (I'm even talking about my 16/3.5 AI fish that clearly has a peak infinity sharpness), the 15/4.5 has a broad range of focus turn that all appear to be pretty close in sharpness in the center of the frame - never really looked in the corners while focusing to make sure they are "optimal".
I'm still interested in the native E mount version just for convenience of having the focal length/aperture in the EXIF.
p.5 #14 · Official: Voigtlander 15mm f/4.5 III E-mount
I just have a hard time seeing the corners. Actually this morning testing for the extreme corners I had a hard time lining things up. But it's not that normal for me anyway. Usually you focus on center
p.5 #15 · Official: Voigtlander 15mm f/4.5 III E-mount
Fred Miranda wrote:
The Samyang 14 is very similar in that respect. Hard to see peak sharpness especially when not focusing close to wide-open. With the Loxia 21 or even the 16-35/4 focus-by-wire zoom, you know when you nailed focus and it's much easier to evaluate astigmatism, field curvature, etc.
But, this image shows a case for astigmatism at the extreme edges of the frame. I will wait to receive Guy's copy "The Choppy" to further evaluate this lens.
Here is a section of the above image link showing how sagittal and tangential lines are focused in a different place at the extreme edge area....Show more →
I think the trick would be to focus bracket in tiny increments in the corners when doing this test.
p.5 #16 · Official: Voigtlander 15mm f/4.5 III E-mount
DavidBM wrote:
I think the trick would be to focus bracket in tiny increments in the corners when doing this test.
I did bracket in small increments because this is actually the performance I get from my M-mount version. I really wanted to see if there was any improvement in the E-mount version, so I went out of my way to make sure I got this right.
So, I went from the 2m mark until the infinity hard stop (where it looks the sharpest at 12x mag. in the viewfinder) in very small increments. I took 5 images. At the 2m mark it looked worse but once it got close to the infinity hard stop there was virtually no differences at 1:1.
The best crop was actually at tad before the infinity hard stop for both my copies.
The extreme edge crop I posted on the first page is the best it can be from the lenses I have. I'm getting a new one next week. I'm starting to think I've tested 3 lemons so far.
Let's see.
p.5 #17 · Official: Voigtlander 15mm f/4.5 III E-mount
Fred Miranda wrote:
I did bracket in small increments because this is actually the performance I get from my M-mount version. I really wanted to see if there was any improvement in the E-mount version, so I went out of my way to make sure I got this right.
So, I went from the 2m mark until the infinity hard stop (where it looks the sharpest at 12x mag. in the viewfinder) in very small increments. I took 5 images. At the 2m mark it looked worse but once it got close to the infinity hard stop there was virtually no differences at 1:1.
The best crop was actually at tad before the infinity hard stop for both my copies.
The extreme edge crop I posted on the first page is the best it can be from the lenses I have. I'm getting a new one next week. I'm starting to think I've tested 3 lemons so far.
Let's see....Show more →
I reckon that pretty much settles it! Be interesting to see how Choppy shapes up, but I'ld put good money on him being very similar. Cosina seem to have pretty good variance, and the designs are tricky to make, so three lemons in a row *whose lemonness is pretty much the same* seems, ah, unlikely... And in any case, even though it's pretty slow it's a very compact lens and it surprises me how good it manages to be on a very high rez sensor! Especially without resorting to four double sided aspheres and every element bar two being low dispersion like the new Batis....
p.5 #18 · Official: Voigtlander 15mm f/4.5 III E-mount
This is the test image I made with thew 15mm CV III M mount when I 1st got it. The link is to a 50% sized image if I recall correctly. Like Guy's, this copy seems to have very sharp corners. Taken at ~F9 on an A7R, a good distance away but not infinity. It was processed in LR with Auto CA on
p.5 #19 · Official: Voigtlander 15mm f/4.5 III E-mount
Fred Miranda wrote:
This is a tough test for any lens but you know which lenses come on top. It's very tough on an ultra wide.
The best ultra wide lenses I've tested so far are the 15/2.8 Distagon, Canon TS-E 17/4L and even the FE 16-35/4 perform better on that area (10%) at infinity.
I am curious Fred - have you tested the Tamron 15-30?
p.5 #20 · Official: Voigtlander 15mm f/4.5 III E-mount
Looks like a nice copy Mike. I'll find some sample images from mine I shot in NY . See how those corners look. Mike does yours have the petals on.
mcbroomf wrote:
This is the test image I made with thew 15mm CV III M mount when I 1st got it. The link is to a 50% sized image if I recall correctly. Like Guy's, this copy seems to have very sharp corners. Taken at ~F9 on an A7R, a good distance away but not infinity. It was processed in LR with Auto CA on
To make it harder, there are very little changes in focus at 12x magnification when slightly moving the CV 15 focusing ring.