VIgnetting and the 40mm Nokton 1.4

[leon]

I've only just got my CV 40mm nokton and have run a few test rolls through ... I find that when I use a standard hoya filter on the lens (with the slotted lens shade attached too) I am getting some severe vignetting, especially if the lens is wide open. It's fine without any filters (but still with the shade on) Anyone else having this difficulty?

click here to see an example ... this was taken at 5.6 and using teh hyperfocal markings on the barrel - all sharp as it should be , but just look at those corners. It was a bit expensive for it to turn out to be a glass holga 🙁

 

[Doug]

How about WITH the filter but WITHOUT the lens shade? Try a different filter? Seems unusual for the lens/shade combination to be that critical that the addition of a filter would cause the vignetting. Usually there's enough leeway, especially with lenses like the 40 that aren't all that wide, to even use longer hoods without trouble. A final option would be to get a rectangular hood for it... hopefully with a cutout at the upper left, but that could be added too.

 

[sockeyed]

I use the 40mm with its hood but no filter, and I haven't noticed any vignetting at any aperture.

 

[pvdhaar]

Although I don't personally own the 40/1.4, I agree that the vignetting shown here at f5.6 is very strong.

Generally vignetting that is caused by light fall-off either from the lens or the filter clears when you stop down a couple of stops. As this doesn't appear to happen here, it seems that the edges of the shade are now protruding in the corners of the frame. As closing the aperture down does not change the field of view, the vignetting doesn't go away, only the edge will become more pronounced.

So my guess is that you'll need a slim filter with this shade. They're more expensive than the thick ones but may do the trick. Beware though that not all slim filters have a front thread for stacking other filters or shades...

 

[unsharp]

I used my Nokton 40mm with a std Hoya UV and the hood and to my memory never had any vigneting at f/5,6. A lens of this focal length shouldn't.

If you still have vignetting without filter and hood it's just very strange, as there in my mind is nothing that could cause one lens to vignet more than another one of the same design.

Sometimes I'm surprised by the creativity of introducing errors in a copy that minilabs have. Is your scan from a neg or the copy?

For the record, I think the Nokton is a good lens.

 

[alansoon]

I haven't had any vignetting. I use this without a filter but with a hood. Btw, I agree, this is a great little lens. Ok, it's not THAT little.

 

[leon]

Sometimes I'm surprised by the creativity of introducing errors in a copy that minilabs have. Is your scan from a neg or the copy?.

Unsharp - I develop and print all my own stuff - the picture is from a neg scan with only white and black point adjusted and a touch of USM, no other manipulation.

I've just dev'd a test roll with shots of the same subject with all the different combinations ... I'll post the results as soon as I have them

 

[leon]

ok - done my tests


here are the results

click here to see the shots all taken focused on the subject; and'


click here to see the shots all taken focused on infinity.

As you can see the shade/filter combination have no effect on teh results, the vignetting is there no matter what combination (and seems to be worse at infinity). DO any Lens experts out there know of any defects that might cause this lens to behave in this manner?

I'm going to print these conventionally to have a final look (just to out rule and scanner mishaps) then if stilla problem, I'l be sending the lens back to Robert White for replacement.

Why cant life be simple??? :bang:

 

[denishr]

Leon, my 50/1.5 Nokton also vignettes wide open. But, yours is excessive 🙁
Check out my thread HERE.

In short, I think some vignetting (i.e. light falloff in the corners) is inherent in fast lens design when the lens is used wide open. But, it should vanish by f2.8.
However, as I said, your examples show excessive light falloff.

I'd advise to return the lens if you can.

Denis

 

[leon]

Utterly Confused - an update

Utterly Confused - an update

Now ... something just a little bit weird is going on 😕

I've just got a colour film back from the lab that shows absolutely no vignetting on it - click here for an example. Many of the shots on this roll were taken in the woods with low light and wide apertures ... and no vignetting.

I've also scanned a few other frames from the same roll as the test shots above - click here or here for examples. There is no vignetting that I can tell (other than natural sky deepening) on these shots either.

I think this is going to need much more investigation 🙄

 

[Benjamin Marks]

I would like to offer an observation. You haven't said what kind of camera you are using, but if it is a horizontal-travel shutter (like in the Ms) the vignetting you are experiencing could be the result of a slow second curtain. I had this happen recently with a Nikon F3. The second curtain hangs for just an extra split second as it begins to travels, resulting in more density on one side of the negative. A CLA is warrented in this case.

If you are using a Bessa with a vertical travelling metal bladed shutter, then I'm stumped. Do you get this result with any other lens? The thing is that a shutter's performance MAY vary depending on how often you work the shutter, when the last time it was CLA'd, gummed up lube and the like. I find it odd that the vignetting should come and go like that.

 

[leon]

Benjamin - it's a Bessa R3A that was new at the same time as the Nokton

 

[leon]

Update

Update

I've been in the darkroom printing from the test negs this afternoon and all fstops up to f5.6 show significant vignetting 🙁 . The lens will be returned for a new one on Monday.

 

[leon]

update - replacement lens works like a dream 🙂

 

[Doug]

Well, excellent news! I am very curious what might have been wrong with the first Nocton. Trying to imagine what assembly-line error led to that result... I hope it gets back to Cosina for examination.