Does the 40/1.4 Nokton shift focus?

[ampguy]

may want to read here

may want to read here

post # 151 over here

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I can't for the life of me believe that focus shift would differ between samples of the same lens. Perhaps infinity calibration would, and that could make a difference in what you see and how you like it.

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[Makten]

post # 151 over here

Sorry, but I don't believe it until I see some pictures. How on earth could two samples of the same lens shift focus differently? Either they don't, or they are not of the same optical formula.

Back/front focus is something completely different, which of course can be worse with one particular lens, because of the calibration of the focus cam helical.

 

[ampguy]

Here is the way I test for focus shift, at minimum distance:

Camera is on tripod, at minimum distance, using laser and sonar measuring devices.

Focus is 0.70m to "A" in Tabasco. Each Hamtaro figurine to the right is 1.5cm behind the Tabasco bottle, or figurine to it's left.

Each figurine on the left, is 1.5cm in front of the Tabasco bottle, or to the figurine on it's right.

The lens used for this test was the CV 40/1.4 MC on an M8. I'm pleased that there is either none, or indiscernable focus shift for this particular lens, at minimum focus distance.

Test results are here

I wonder how the CV 35/1.4 would do in this test??

 

[Rogrund]

Interesting test, but I wonder if the photos are correctly marked? The glass jar in the window is almost sharp at f2.8 but totally out of focus at f16. That doesn't make sense, or did I get it wrong?

Here is the way I test for focus shift, at minimum distance:

Camera is on tripod, at minimum distance, using laser and sonar measuring devices.

Focus is 0.70m to "A" in Tabasco. Each Hamtaro figurine to the right is 1.5cm behind the Tabasco bottle, or figurine to it's left.

Each figurine on the left, is 1.5cm in front of the Tabasco bottle, or to the figurine on it's right.

The lens used for this test was the CV 40/1.4 MC on an M8. I'm pleased that there is either none, or indiscernable focus shift for this particular lens, at minimum focus distance.

Test results are here

I wonder how the CV 35/1.4 would do in this test??

 

[ampguy]

Thanks

Thanks

You're correct, the Smugmug gallery filename numbering ordering isn't working. I've corrected the comments to reflect the exact apertures and shutter speeds used.

Interesting test, but I wonder if the photos are correctly marked? The glass jar in the window is almost sharp at f2.8 but totally out of focus at f16. That doesn't make sense, or did I get it wrong?

 

[baycrest]

I can't for the life of me believe that focus shift would differ between samples of the same lens. Perhaps infinity calibration would, and that could make a difference in what you see and how you like it.


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Sample variation exists regardless of manufacturer. Variable factors include the timing of the production run (early vs. mature after all the bugs are worked out), sourcing of parts and manufacturer's QC.

Voightlander also experiences variation, try also reading about the 21mm LTM versus the M mount variation for the same fl.

So many usually test out there lenses soon at the time of purchase or soon thereafter to ensure the lens in properly aligned, focus shift is within known parameters for that lens etc.

When you get a good 40mm Nokton, other than the bokeh, which I mentioned previously, you'll really be pleased with the results.

Season's Greetings,
Rob