Voigtlander 28 Ultron Focus Shift Sample Variation

[rsolti]

I am looking to get a 28mm lens for an M8....wanting the 35mm view. I would prefer something fast and am considering Voigtlander with either the 1.9 or 2.0 lenses. I have read a lot (even review sites such as Reid) talking and showing examples of how bad the focus shift is on the 28 f/2 Ultron. My question is, does the magnitude of focus shift vary between samples? I have heard some people claim that the f/2 Ultron is almost as sharp as the Cron from f/2 all the way down and some claim how horrible performance is stopped down. Which camp to believe? Would focus shift on this lens be different on an M8 and M8.2 due to the difference in where the framelines are set? Is that why film doesn't see focus shift as much as digital?

Re: the 1.9 Ultron. What are the main drawbacks vs the Cron and f/2 Ultron? Flare performance, size? Reids review shows sharpness almost on par with the Cron starting at f/2

 

[sper]

I've used the Ultron 2.0 on an M8. It was a nice combination. It's very sharp, but low contrast wide open will give you the appearance of softness, even though there is acceptable detail rendered. Stopped down it preforms admirably, as any modern lens should.

I don't think you will notice the focus shift, unless there is something very wrong with your copy. I was able to focus accurately almost every time, even wide open on the M8, and of course on film as well.

If you want better performance you will have to pick up a Summicron or a Biogon, but in either case you're going to lose 1 stop, or 1 hefty chunk of change. Since Leica lenses are never worth their premium (in terms of absolute photographic potential), I'd opt for the Ultron.

Here are some examples! I think the low contrast is evident, but judge for yourself.


Untitled Girlfriend Portrait by marksperry, on Flickr


Untitled Girlfriend Portrait by marksperry, on Flickr


Sunny Frecks by marksperry, on Flickr

 

[dow]

This might be a stupid question - but is focus shift an issue for film shooters? Or is it a digital issue alone?

 

[sper]

It exists for both, but is less of an issue for film. Could be becasue there is no "view at 100%" command on a slide or enlarger. 🙂

 

[back alley]

the untitled girlfriend is very cute...

 

[Dan States]

Focus shift is a characteristic of lens design, not assembly. It is either in the design or it isn't. People who claim to have found lenses that shift and others that don't are just not testing scientifically. As long as the amount of shift is covered by the depth of field at the set distance it won't really matter. It becomes a big problem with cropped sensor digital cameras because the effective depth of field is reduced at any given distance (you are simply magnifying the image more, emphasizing any image defect, not just focus shift).

 

[rsolti]

Focus shift is a characteristic of lens design, not assembly. It is either in the design or it isn't. People who claim to have found lenses that shift and others that don't are just not testing scientifically. As long as the amount of shift is covered by the depth of field at the set distance it won't really matter. It becomes a big problem with cropped sensor digital cameras because the effective depth of field is reduced at any given distance (you are simply magnifying the image more, emphasizing any image defect, not just focus shift).

So, the closer the object in focus the more shift that will occur....or more you will notice the shift?

 

[rxmd]

I have read a lot

I nowadays recommend people to read less. In the case of CV lenses, there appears to be some sample variation indeed, but bias variation and habit variation among Internet posters is probably a more significant factor than sample variation among lenses.

Would focus shift on this lens be different on an M8 and M8.2 due to the difference in where the framelines are set? Is that why film doesn't see focus shift as much as digital?

Frameline size won't have any effect.

As someone already pointed out, the main reason people don't see as much focus shift with film is that it is more difficult to pixel-peep.

Focus shift is one of those things that matters largely only for a small (but vocal) minority on the Internet, and that historically hasn't mattered for the vast majority of photographers.

This is true even without going into the question whether it matters in everyday shooting, as opposed to desktop pixel peeping in staged closeup shots of slide rules and diagonal bookshelves. The stereotypical focus shift nerd is the kind of person who illustrates the phenomenon with a staged closeup scene that shows 5mm of shift on a ruler, claiming that "if this had been a portrait, focus might have been on the glasses rather than the eye" - all the while spending his time shooting staged closeup scenes rather than portraits.

There is really no remedy other than seeing for yourself whether it matters for you.