UV filters on Digital *istDs

I am new to the forum, so hope I have found the right way to use it.

I recently purchased a *istDs body so that I could use the Sigma lenses that I had for my Pentax Mz5N. To protect the lenses I use a UV filter permanently on the front. For film use I did not find this a problem.
However will they affect the digital use/exposures?

The filter shouldn't degrade the image on a digital sensor any more than it does on film.

Personally, I try to avoid the use of filters unless I actually need them. I know they help to protect the lens, but they inevitably interfere with the light path, and I would prefer to take care and risk damage than (slightly) impair the quality of all my images.

But it's a very personal choice. In rough conditions outdoors I will fit protective filters, but by default, I don't.

Pentax multi-coating is in fact extremely hard. When they first brought it out, they advertised it with pictures of cigarettes being stubbed out on the lens!

Of course, if you're using Sigmas, it's another story.

G

I totally agree with George - don't fit filters anless you need them photographically.

I know the arguments about protecting the lens are there, but how often have you damaged a filter? Never? Then that's how often, hopefully, you will damage a lens.

I think a lens hood is far more essential - it protects from flare and also protects to some degree from any physical damage.

Others may well disagree, and if so I'm sure they'll say why!

I've always used UV/skylight filters, it's easier to clean a flat piece of glass than a curved lens element but your arguments against using them make perfect sense

Am I the only one searching for real UV filter to use when I want to cut on distant "haze"? Does it really make a big difference? I live in a beautiful mountainous zone where the mountain peaks far away are almost always very "foggy"...

I have the Cokin A series and will buy their UV (as soon as I can find one) for testing. Any experiences from you experienced folk?

If you have distance haze then a filter may well be necessary. Personally, I have never found the UV filter to be enough, preferring the Skylight or even an 81A with colour film. For black and white film then a red filter is the most effective, or the Infra-red one even more so if you are after special effects with IR film.

Digital is a different issue, as so much can be done post capture. What you can't do is cut through haze once it is recorded, so a filter may have a use there. Even if you eliminate the problem colours in channel mixer, the scattering of light generally will have caused some degradation, so better to eliminate it in the first place with a filter.

However, for general purposes I still think the principle of only using filters when necessary is the right one for me.

[quote]I know the arguments about protecting the lens are there, but how often have you damaged a filter? Never?

Oops - first time at trying to use the quotes - and seem to have got it wrong - sorry!
Andy

Your tale about the camera strap breaking reminds me of a mishap I had. I was changing a lens while walking down a street in Milan and dropped a Pentax 120 lens. I tried to get my foot under it to break its fall but this resulted in me kicking the lens down the street. The only damage was a small chip on the body and no optical damage at all! I am still using the lens today.

I can’t remember if it had a filter on at the time but probably not. I used to worry and keep a filter on all the while but I don’t any more. I agree with what has been said and use them only when they are needed and would never use one without a lens hood.

Regards,
Dave.

A similar, and recent, story from me...
I have Hoya Pro 1 filters on my main lenses (99.7% light transmission). While on holiday in the west of Ireland last week, my SMC-FA 24-90mm was on a film body, in a case and got knocked off a seat while on a boat (my 18 month son's legs were flaying rather wildly at the time) and fell nose down. There was the stomach-churning sound of breaking glass.
The filter had taken the impact and splintered (I can supply photos ), and thankfully the lens was completely unharmed.

...now whether the lens would have been ok without a filter I couldn't say...

In any case, it's interesting to hear about the hardness of the SMC coating (not that I'm going to put it to the test!!!!)

Matt

A few years back I dropped my camera off a mountain. It landed lens down. Fortunately I'd been using a cir-pol filter at the time, which took the brunt of the impact. Ever since I've had two rules:

1) Keep the camera strap around your neck at all times, no matter how tempting the shot.

2) Always have a UV/skylight filter on your lens even if you don't really need it.

If you're really careful you may only drop a lens onto gravel, rocks, metal spikes etc. once in your lifetime, but when you do it will inevitably be your favourite (and most expensive) objective that's left with a dirty great scratch across the front.

Steve

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I make my comments from the perspective of a film camera user, as I'm still waiting for the right digital camera (Pentax, of course)

I leave a filter on all my lenses (generally a skylight), which means that when handling the lenses, if I get finger marks on the front, then I only have to clean the filter. I have never had the filter save the lens from impact damage. The only time I damaged a system, it was the camera that hit first, and upset the shutter, permanently.

When I take photos, then I decide whether to remove the filter. I only leave the filter on for long distance views, landscapes or objects in the distance, where there will be significant ultra violet hazing. I would expect the ultra violet to have a similar effect on Digital cameras, but it really depends on the sensitivity of the sensor to the shorter wavelength light and ultra violet. If the sensors are not sensitive in this region, then an ultra violet filter is superfluous, and probably degrade the picture.

As for film cameras, the sensor is definitely sensitive in the infra red range, and this sometimes distorts the apparent colours of blue flowers particularly, making them appear mauve. In this case, a blue filter (82) is essential to remove the invisible infra red light, which changes the colours recorded by the camera.

Since the colours you are trying to correct for are outside the visible range, they cannot be corrected for by the limited colour gamut available post capture, so filters are still essential in these areas.

So, in my view, the filters in these cases are only used to align the colours the camera records to those seen by the human eye. They should not be adding a colour cast, although any filter is an extra piece of glass and a couple of surfaces to interfere with the image.

This is one of the original religious wars in photography. This question has been argued as far back as I can remember (the 1950's).

My personal experience is that:

1 - I don't notice any difference if I use a well-maintained quality filter on the camera, and

2 - Keeping the filter clean is critical, it is now the front element of your lens system, and

3 - Having fallen down a flight of stairs with a VERY expensive lens on my person, I found that after I dug the broken filter's threads out of the front of the lens, it was in a lot better shape than I was!!!

The only lens that I 'damaged' was my F35-135, whilst fitted to my SFX.
It fell off a seat in Malaga airport, it was inside a padded holster case with filter and lens cap fitted. Despite the padding and the fact that it only fell 18" or so, the lens barrel became loose. At first, everything seemed ok and the lens was perfectly usable but I soon discovered that the barrel could be unscrewed and removed, complete with front element.
Fortunately, our holiday was over and there was a strong chance that the barrel, when extended under zooming, could fall out and so I promptly sent it to Pentax for repair upon returning home.
That was six or seven years ago and the lens is still perfectly fine, the filter didn't play a role in the incident but I thought I'd mention it anyway.

I think it goes to prove however, that no matter how tough you think your gear is or how well protected, you can never keep it too safe!

Hi,
I have to put my hand up to being in the camp that uses filters most of the time. However, I do make sure that they are good quality. Over 25 years or so, I have managed to dent the thread in 5 filters which, bearing in mind most of my lenses are the older metal bodied ones, would have meant dented lenses. It is a mute point whether this is as imprtant with the more modern polycarbonate lenses. They are not likely to dent (but at least a dent can be eased out of a metel lens). IMHO, a more important point is not dents but cleaning. The SMC is hard but not that hard. More lenses are damaged by overzealous cleaning than any other reason. Over the years I have had to reject many secondhand lenses because of cleaning marks. Because of this I use air pressure, if this doesn't work, I will resort to a very soft sable brush and only when this fails will I use a cloth. In this case it will be a microfiber one which has been cleaned. (Normally it is not the cloth that does the damage but the dirt in it!) The main reason for this is that in the I would sometimes lose shots becuase I had a lens cap on to keep the lens clean. By using a filter, I can walk around with the cap off and not worry about dust etc. If the filter ends up with cleaning marks, it is relatively easy to replace.

As a final thought, I would like to add to the comments made by Taliety. I dislike the term "haze" filter because it is a misnomer! They can do absolutely nothing for any distortion caused by heat (haze) or the softening of a picture caused by particles in the air such as dust or pollution that becomes so apparent with long lenses and is normally called haze. However, they are good at reducing the softening caused by UV light which is not apparent to the naked eye and is stronger at higher altitudes due to the lower filtration caused by the atmospere. As such they are very useful up mountains and almost essential in Air-Air photog.

Kim