mfogiel
Veteran
I have been struggling somewhat with the choice of a 28mm lens. So far I have tried the v2 Elmarit, Elmarit ASPH and Biogon. I have deliberately excluded the apparent king of the hill - the Summicron , because I consider its hood far too big for a carry around lens, and I by principle dislike shooting without hoods, and with unnecessary filters. So I set my eyes on the new Ultron 28/2, which I have bought from a fellow RFF'er here.
Now, there has been a lot of talk about the problem of this lens, which supposedly is the focus shift, so I wanted to check what is the issue.
I have made a simple test from a demanding distance of 1m ( if it does not create problems at this distance it is unlikely you will ever see it in real life, intermediate to long distance shots). I put the camera on a tripod and have used a sharp film (Ilford FP4+) developed in one of the sharpest dvelopers (Presysol EF). In real life, where I use Tri-X handheld most of the time, it will be highly unlikely that I would ever get anything sharper than this.
I have set up a series of beer cans placed diagonally at distances of 10 cm one from another. You will see the shots of the whole row, and of the focus point for each of the F stops from wide open to F 8.0.
Please look at the examples, the crops are only slightly reduced and correspond to an enlargement of an A3+ size at 300 ppi. There has been no sharpening applied, I have only adjusted the level to put the contrast back to the normal. and the adjustment ha been the same for all frames. All scanned at 4000 dpi on Nikon CS 9000.
F 2.0 and crop
F 2.8 and crop
F 4.0 and crop
F 5.6 and crop
F 8.0 and crop
My take on this is as follows:
while you can observe that the best point of focus shifts back as you stop down, the resolution at the intended plane of focus is acceptable at f 2.0 (where it focuses correctly), becomes strong at f2.8 and remains so through f8.0, which means , that the DOF is wide enough to take care of the focus shift. It might be, that for surgical precision you would have to focus closer at intermediate apertures, but since I can see no visible advantage at the level of 4000 dpi which is the max resolution of my scanner, then I think the point is moot.
Obviously, we are talking film here, so the emulsion depth is giving a helping hand, which does not become available when one shoots digital, but this is not my problem, as I do not intend using digital for B&W photography as long as the tonal quality will not match that of film.
Please, take a look yourself and comment if your conclusions differ, as I am eager to know your opinions too.
Now, there has been a lot of talk about the problem of this lens, which supposedly is the focus shift, so I wanted to check what is the issue.
I have made a simple test from a demanding distance of 1m ( if it does not create problems at this distance it is unlikely you will ever see it in real life, intermediate to long distance shots). I put the camera on a tripod and have used a sharp film (Ilford FP4+) developed in one of the sharpest dvelopers (Presysol EF). In real life, where I use Tri-X handheld most of the time, it will be highly unlikely that I would ever get anything sharper than this.
I have set up a series of beer cans placed diagonally at distances of 10 cm one from another. You will see the shots of the whole row, and of the focus point for each of the F stops from wide open to F 8.0.
Please look at the examples, the crops are only slightly reduced and correspond to an enlargement of an A3+ size at 300 ppi. There has been no sharpening applied, I have only adjusted the level to put the contrast back to the normal. and the adjustment ha been the same for all frames. All scanned at 4000 dpi on Nikon CS 9000.
F 2.0 and crop
F 2.8 and crop
F 4.0 and crop
F 5.6 and crop
F 8.0 and crop
My take on this is as follows:
while you can observe that the best point of focus shifts back as you stop down, the resolution at the intended plane of focus is acceptable at f 2.0 (where it focuses correctly), becomes strong at f2.8 and remains so through f8.0, which means , that the DOF is wide enough to take care of the focus shift. It might be, that for surgical precision you would have to focus closer at intermediate apertures, but since I can see no visible advantage at the level of 4000 dpi which is the max resolution of my scanner, then I think the point is moot.
Obviously, we are talking film here, so the emulsion depth is giving a helping hand, which does not become available when one shoots digital, but this is not my problem, as I do not intend using digital for B&W photography as long as the tonal quality will not match that of film.
Please, take a look yourself and comment if your conclusions differ, as I am eager to know your opinions too.
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squirrel$$$bandit
Veteran
Whoa, you can get Hoegaarden in cans where you live?!?
mfogiel
Veteran
Haha ! A nice comment I was not expecting...
Sjixxxy
Well-known
My first thought too was about how foreign Hoegaarden in a can is to me.
Pickett Wilson
Veteran
mfogiel, now we know the true meaning of "focus shift." 
sanmich
Veteran
And the small bottle in the middle is what you need to drink on the morning after you drink all the rest?
Patience my friend, I am sure someone around here will react to the point...
Patience my friend, I am sure someone around here will react to the point...
calajava@gmail.com
calajava
mfogiel, thank you for such an comprehesive test, I am seriously considering this lens. great read.
elshaneo
Panographer
I'm currently selling my Voigtlander VM Ultron 28mm f/2 which is like Brand New. Check the Classifieds !!!
Please let me know if You're interested to buy it, thanks ;-)
Please let me know if You're interested to buy it, thanks ;-)
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Krosya
Konicaze
Thanks for the test!. From what I have seen I like this lens and I'd even get one if I didnt already have M-Hexanon 28. ANyway, I'd love to hear your comments on this lens when compared to the other 28mm's that you already have - handling, image quality, flare, etc.
ampguy
Veteran
Mike, I'm not sure where to start... But if you like the images from the lens, excellent, that is all that matters!
nzeeman
Well-known
thanks for the test - it is good to see that there is no focus shift. it is very interesting how someone always spread rumours when new CV lens come... always about focus shift , distortion and softness - and they almost never exist... it seems that other camera manufacturer have a lot of people on his pay list which have a job of spreading that kind of stuff. they would do better if they fire those people and lower prices of lenses instead...
about the lens - very nice bokeh and contrast and also free of distortion - too bad i am not 28mm and wide angle guy - i would surely take this lens.
about the lens - very nice bokeh and contrast and also free of distortion - too bad i am not 28mm and wide angle guy - i would surely take this lens.
visiondr
cyclic iconoclast
Slightly off topic, but relevant to the OP's initial observation that the Leica Summicron 28's hood is too big; Can you simply buy an aftermarket hood for the 'cron or use the hood from the Ultron 28/2 (sold as an accessory to the lens, I'm sure)? It all depends on filter thread size. Does anyone know?
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hans voralberg
Veteran
I can't see any focus shift, will put this lens on the buying list now, thanks mfogiel.
Paul T.
Veteran
Well, there is focus shift. In the f/4.0 image, the cans behind are reasonably in focus; the ones in front aren't. THis shows that the central focus point IS shifting backwards with a smaller aperture.
But the tests also show that the focus shift is not a problem, as the central point of focus does remain sharp. But this is valuable information for anyone who relies on depth of field to keep a range of objects in focus.
But the tests also show that the focus shift is not a problem, as the central point of focus does remain sharp. But this is valuable information for anyone who relies on depth of field to keep a range of objects in focus.
Cron
Well-known
.......... and an amplifier with tubes
thanks for showing the results
thanks for showing the results
visiondr
cyclic iconoclast
Further to my query, the CV Ultron 28/2 and the Leica Summicron 28/2 share the same 46mm filter size. However, it appears the CV hood attaches to threads on the outside of the barrel, not the inside threads.
tritiated
Well-known
I think I want a nice cool beer, hmm - a nice refreshing one..there's a pub not too far away, I think I will have a Hoegaarden! Their glasses are immense and sturdy! awesome
noimmunity
scratch my niche
Thank you for the tests.
The summicron 28 does not have to be used with a hood most of the time, in my admittedly less than stringent experience.
You can pick up an after market hood from heavystar that is much smaller than the original.
Without the hood, it barely blocks any of the 28 frame on the ZI. (maybe 3%).
With the heavystar hood, it blocks the right lower corner, about halfway towards the lower right corner of the 85 frame when the lens is fully extended at minimum focus.
OT: I think you would be pleasantly satisfied by the performance of the 28 cron.
The summicron 28 does not have to be used with a hood most of the time, in my admittedly less than stringent experience.
You can pick up an after market hood from heavystar that is much smaller than the original.
Without the hood, it barely blocks any of the 28 frame on the ZI. (maybe 3%).
With the heavystar hood, it blocks the right lower corner, about halfway towards the lower right corner of the 85 frame when the lens is fully extended at minimum focus.
OT: I think you would be pleasantly satisfied by the performance of the 28 cron.
dpap
Member
great job Marek....now, can I have my lens back?
R
Roberto
Guest
Are those in the back 300B?
Rob.
Rob.