I have just bought an M6 ttl with 35mm 1.4 ASPH,I won't be able to eat or put petrol in my car for the next few months,but hey,who cares. The problem I have is that I get bad vignetting at f1.4 to f4 when I use the square hood.Is this normal?

-- Phil Kneen (philkneen@manx.net), January 12, 2002

Answers

No it is not normal. It sounds as though you do not get the vignetting if the lens hood is left off. If that is the case, are you putting the lens hood on properly? First you have to turn the hood's locking ring so that the two dots are not in alignment. The hood should then click into place on the lens after which you turn the hood's locking ring to align the two dots. If you are using a UV filter, it may be that you are attaching the lens hood to the filter and not the lens proper. This is easily done if you do not use the hood's locking ring properly.

Forgive me for mentioning the following simple things but it best to cover all the bases. The hood is retangular not square. The long part of the retangular hood should be horizontal with the hood cutout visible from the camera's viewfinder and the white dots on the hood facing up.

-- John Collier (jbcollier@powersurfr.com), January 12, 2002.

John,It's definately on right-if it went any further back,which it can't,it would cover the f.numbers.I have just checked the test film I did and it is only noticable upto f 2.8,however in the instructions it says there is no noticable vignetting even at f 1.4.

-- Phil Kneen (philkneen@manx.net), January 12, 2002.

Phil:

I'm with John on this one. I have never had a vignetting problem with the hood on my 35 asph 'Lux. Are you using any filter on the front of the lens? If it is overly thick, I suppose it could be the cause of your vignetting... As John sugested, shoot the next roll without the hood and both with and without any filters and see if you still have the problem.

It is alternatively possible that you mis-loaded the film, which perhaps could cause the appearance of vignetting.

-- Jack Flesher (jbflesher@msn.com), January 12, 2002.

I have not used the lens with a filter.How could mis-loading the camera cause this? perhaps that is the problem?

-- Phil Kneen (philkneen@manx.net), January 12, 2002.

Phil:

If the film was not lined up properly with the guide rails, it can be exposed off-center and generate what looks like a vignette along one of the horizonatal edges. Look at the negatives and make sure there is a nice, clean unexposed border all the away around the image, and that no part of the exposure hit the sproket holes. If this is not the case, then you likely mis-loaded the film.

-- Jack Flesher (jbflesher@msn.com), January 12, 2002.

The negs are fine,however they are about 1-2 stops underexposed,but that's my fault.I have only put one roll through as a test film.Anyway,underexposure wouldn't cause vignetting......would it? I do appreciate your help on this.

-- Phil Kneen(Isle of Man,UK) (philkneen@manx.net), January 12, 2002.

Actually, underexposure can accentuate the inherent (natural) vignetting present in all lenses. especially 2 stops worth. The 35 asph 'Lux has about 2.5 stops of natural vignetting in the corners (according to Erwin Putts) at f1.4, but it gets progressively less as you stop down. I would be willing to bet that this is what you are seeing. Try another roll, properly exposed, with and without the filter in normal light. (For some exposure tips, see the earlier responses to Bill Bolger's metering question post a few days ago.)

-- Jack Flesher (jbflesher@msn.com), January 12, 2002.

John,I think you are right.I put the negs through my canoscan 4000 to view them.The more the underexposure,the worse vignetting.There is a couple of shots that are shot at f1.4 and 2 stops under and the vignetting is terrible.So,I don't think you are right,I know it! Do you recommend using a good uv filter(BW,etc) or is that question opening a whole can of worms......?

Thanks a million John.

-- Phil Kneen(Isle of Man,UK) (philkneen@manx.net), January 12, 2002.

I think "vignetting" is most often used to describe the physical blocking of light due to obstruction by the lens mount, hood, or limited lens coverage of the film format. I think what you are describing is light fall-off in the corners--a consequence of the optical design. If your hood was causing vignetting, you would see it at most apertures, not just the wide ones.

-- Tim Nelson (timothy.nelson@yale.edu), January 12, 2002.

Underexposure most certainly will make natural vignetting (light falloff at the corners) appear much worse. I have not seen this problem to any significant extent, even wide open at F/1.4 with the 35/1.4 Aspherical. But there is NO WAY you should see "vignetting" at F/4.0. It should be all but gone by then. You need to run another test with properly exposed slide film. Perhaps you could post some of the pictures. I need to see the image to evaluate whether what you are describing is vignetting.

-- Eliot (erosen@lij.edu), January 12, 2002.

Cause is neither filter nor hood: if that were the case, vignetting would get WORSE as you close down (induced shadows becoming more defined and obnoxious due to larger DoF).

-- Jacques (jacques.balthazar@hotmail.com), January 13, 2002.