UV & ND Filter question

[ron110n]

Hello, I'm new to LF and starting my first used lens Schneider Kreuznach 180mm f5.6 APO-Symmar on a Toyo View 45G.

Question:
1. Would anyone recommend a UV filter for LF lenses like Heliopan UV Filter-SH-PMC, or no UV filter at all is better.

2. Is wide open f-stop (f5.6) recomended?

3. How about B+W ND (Neutral Density) 103 and 106 filters to open the lens on broad daylight. I understand that most LF people shoot f11 to f22.


Sorry for my stupid questions. My only experience are 35mm and 6x6 MF.
BTW, I haven't shot a picture yet on my 4x5 camera.

Thanks in advanced

Ron Mutuc

[Bob Salomon]

The answers are really not different then for any other format. A UV or skylight (if you are shooting color) from a high quality manufacturer will not materially impact optical quality as long as the filter is in front of the lens and will add protection to the lens. The SH-PMC will give much better results then standard coatings and other MC coatings.

Wide open is always recommended for focusing. Optimal performance will start about two stops down and go on to f22 with your lens. Beyond f 22 you will start to be in diffraction.

A quality ND filter, Heliopan makes them with densities of 0.3 (1 stop) to 3.0 (10 stops) is always useful like most filters for a desired effect or, with ND, to bring the light down so you can shoot at a required aperture or exposure time. MC ones, where available, are best.

[Steven Tribe]

Dear Bob!
Could you explain why ND filters are best when MC (multiple coated)? I thought that the idea behind coating was to increase the passage of light at the air/glass phase. Surely the slight light loss with non-coated ND filters has been taken into consideration when calculating the ND factor. Or is there some other beneficial effect of coating which escapes me at the moment?

[Joanna Carter]

One of the disadvantages of uncoated filters is that you can get effects like the "ghost" light images as in this picture:

[Steven Tribe]

Could you explain the conditions a bit Joanna? Why are the corner seated couple only registered as a ghost image?

[Bob Salomon]

Dear Bob!
Could you explain why ND filters are best when MC (multiple coated)? I thought that the idea behind coating was to increase the passage of light at the air/glass phase. Surely the slight light loss with non-coated ND filters has been taken into consideration when calculating the ND factor. Or is there some other beneficial effect of coating which escapes me at the moment?

See the ghost images in the picture below. Also the SH-PMC coatings repel dust and moisture to keep the glass cleaner.

[rguinter]

Could you explain the conditions a bit Joanna? Why are the corner seated couple only registered as a ghost image?

Joanna may not have gotten back to you yet. But I understand from her previous posts with this photo that it is an extremely long exposure. That's why the couple is registered as a ghost image... they were in the frame for only a portion of the total exposure time.

I tried this technique several times over the years. Once with an hour-long exposure on the boardwalk at the NJ shore. The people on the boardwalk mostly disappeared but there were a few ghost images of some that stood still long enough to register.

The only problem with my images was I used the wrong film... or perhaps took my shots at the wrong time of the day. The color shifts were rather ugly (not nearly as pretty as Joanna's) and I didn't experiment enough with different films and subject matter to make a decent photo. Cheers. Bob G.

[Ron Marshall]

Could you explain the conditions a bit Joanna? Why are the corner seated couple only registered as a ghost image?

I think she is referring to the ghost images of the ceiling lights.

[Joanna Carter]

Indeed, the exposure was for 17 minutes. Therefore, the couple in the corner were seated for long enough to register, but were moving. You should also be able to make out a light-coloured raincoat at the bar, from a man who popped in for about five minutes.

But, the point of showing this picture was to show the refracted "ghosts" of the light globes, caused by the heavy blue filters I had to use to correct the colour temperature, which was around 2300°K, to reach the 5600°K of the Velvia 100 film. Had I been able to afford coated filters, this may not have been so evident.

BTW, for those of you who are asking why I didn't use a tungsten film; well I went back and used Fuji T64, with less filtration and a shorter 8 minute exposure, and, despite my best efforts, ended up with horribly underexposed sheets with a difficult colour cast.

I would ask the question, of those who know these things, what would happen if I had one coated UV filter, placed in front of everything else? Would it kill the refractions from all the filters behind it?

[Steven Tribe]

Thanks, I had guessed that it was an extreme long exposure with, at least, a colour correction filter. I have always been sold on MC filters, but my question was purely related to the necessity of MC with ND filters which Bob mentioned. I have some irisless fast LF objectives so the use of ND is a very pressing subject. As I am using ND sheet filters in a Copal/Sinar shutter - with small adjustment changes in front (Lee type) as well - MC is not an option!

Joanne, I can't see how a front UV filter would help. It is "light" that is being "thrown around" between the air/glass glass/air surfaces - not just the UV component.