Topic: Filters on lenses

[choppert]

Your thoughts please?

I have a Pentax skylight filter on the front of my favourite lens (single coated Canon 35mm 1.8 ltm) - I lost the lens cap!

Am I losing much resolution/sharpness/other by having a filter protecting the lens?

If I were to ditch the filter and the lens glass gets mucky how do I clean the glass?  What damage can too much cleaning do?

Thanks,


Chops

[Francois]

Many years ago, there was an article in Leica Fotographie on the subject. While they proved that you do loose sharpness, they had enlarged the image to the point where you could count the individual grains of silver.

On the other hand, I've seen so many scratched-up lenses and dinged filter threads to say that the protection filter is important. There was even an article in DIYphoto (the one about doing steel wool photography) where they showed a brand new red line Canon lens with a spot melted in because of the user's carelessness and obsession with ultimate sharpness!

So, my conclusion is that while you do loose sharpness, keep the filter on in case of an accident.

[Mike (happyforest)]

You could always leave the filter in place when the lens is in the bag and remove it before a photo session, or there was a thread here on making your own.

I have heard anecdotal talk that using a filter reduces the resolution, but have not seen test confirming that this is the case. Just seen Francois post and this is the first I've heard that somebody has demonstrated the effect.

I believe that the coatings on the lens are quite robust and that it would take sometime to wear them away with an inappropriate cleaning routine.

My cleaning routine is to use a zerostat (when at home) pistol to null any static then use a blower brush or lens tissue, rolled up with the end torn off to create a brush and then gently wipe away any dust etc.  I would only use a tissue to wipe the lens if there was a grease stain or similar on the lens and then very carefully, I would be concerned about grit on the tissue causing damage to the lens.

Incidentally my 35mm lenses have skylight filters on them but my medium format lens don't. I don't tend to take the medium format into the same inhospitable environments as the 35mm.

Mike

[astrobeck]

and don't forget to use dye free- perfume/lotion free tissue.

I usually give the tissue a blow with canned air to blow out any lint hanging around.

Just last week I dropped a Nikon prime lens with a skylight filter on it.  The filter cracked, but the lens was un-harmed!
Whew!

[Late Developer]

Hi Matt.

I see filters as a trade off between protection from the elements / occasional dings and drops and an imperceptible (at least to my eye) reduction in sharpness.

However, they can have posiive benefits. UV filters are supposed to help cut through haze and improve contrast - particularly useful for uncoated / single coat lenses. Also, I like using yellow, red, orange and green filters when shooting mono and I like a circular polariser when shooting colour / to remove reflections off glass and water surfaces.

Overall. I reckon filters are more of a help than a hindrance. Mind you, I try only to use branded filters such as Nikon, Pentax, Leica, etc. Hoya and Marumi seem fine but I've owned a few unbranded versions in the past and have been suspicious about their optical quality (probably without cause) but a brand name tends to instil confidence.....

[Sandeha Lynch]

As above. 

I use a blower.  And a fresh paper lens tissue - never touch the lens with anything that has already touched something else!  The problem of scratches on the coating (or heaven forbid, the glass) is less about resolution than about losing contrast through flare.  It can happen, and even a new filter can decrease contrast if it's a lower optical quality than the lens itself - somebody once did a stacking test with cheap filters that showed this.

Get yourself a new lens cap?

[LT]

Get yourself a new lens cap?

Get yourself a lens pen ?

[Phil Bebbington]

Oddly, I always used them with 35mm, but, have never used them with MF. I took Leon's advice and got me a lens pen - just the job!

[sapata]

I've been using this for years:
http://www.ror.net/

[original_ann]

Another big fan of the lens pen.  If I use a filter (windy beach days, sea salt spray) I try to go as thin as possible like a B+W or Heliopan. 

[astrobeck]

I've been using this for years:
http://www.ror.net/

a lot of astronomers use that stuff to clean their eyepieces, and binoculars.

I use a lens pen for my eyepieces and my camera lenses.

[Daniel Emami]

Get yourself a new lens cap?

Get yourself a lens pen ?

The Lens Pen is probably one of the best investments I have ever made! My lens cap is missing too and I use the lens pen regularly. It cleans of everything.
I saw one of my friends once made his own lens cap from cardboard and some dutchtape in a barrel form (hope you get the idea). It seemed to be pretty effective.

[DaveMiller]

I find it amazing that anyone can detect any practical difference in the printed results of a filtered as against an unfiltered lens.
Can anyone produce any real world evidence of this? 
The use of a plain filter as a lens protector will alleviate the need for lens cleaning; the filter can easily be cleaned with a lens cloth. It’s generally cheaper to throw a damaged filter away rather than a lens.

[Ordinal]

I certainly can't tell the difference between with a UV or similar filter, and without one, on MF or 35mm - either positive or negative (though to be fair I've not been using them for long with MF).

The main reason I keep a filter on my GS645S, apart from not wanting random dust blowing in, is that it makes it stick out a little more past the bull bar so the lens cap is easier to put on and take off.

[Pete_R]

I find it amazing that anyone can detect any practical difference in the printed results of a filtered as against an unfiltered lens.
Can anyone produce any real world evidence of this? 

There was a review of cheap-v-expensive filters I saw somewhere not long ago but I can't find it now, but there was visible difference in the results as I recall. Didn't take a great deal of notice at the time as I don't use 'protection' filters at all though I do generally use an orange for b&w. I tend to prefer lens hoods for protection.

the filter can easily be cleaned with a lens cloth.

For some reason, I find filters a pain to clean. I use Hoya HMC ones and they are almost impossible to get a streak free finish on them. Anyone else find that?

[Francois]

I'm very lousy at lens and filter cleaning. Worse stuff I ever used was the Kodak liquid lens cleaner. I still have some and hate it. I now use some spray liquid from Omni Kleen. Does an OK job but nothing fantastic there.

[Francois]

I went through a pile of magazine looking for the filter sharpness test. Lucky me, I found it in the first magazine of the pile!

This is an excerpt from Leica Fotografie International, issue 7-92E

[Francois]

Page 2

[Francois]

Page 3

[Francois]

Page 4

[Francois]

Finally, page 5

[Pete_R]

Good find Francois. Not the one I saw but interesting reading. I'll certainly be paying more attention to the "wind and bridges" in the future.

[Francois]

Well, you know this is Leica!
In another issue there was a whole big article on whether one should be allowed to take unsharp pictures with a Leica... I never knew anyone had to ask for a special authorization to do so!

[sapata]

Quite interesting theory about how long the fim is left inside the camera may contribute for a unsharp picture (films and pitfalls)... "1 hour without shooting please advance the film crank twice" some of my films are left inside the camera for a year!

Funny to see the image of someone taking a picture on the top of the second tower on the sharpness comparison photographs

[Photo_Utopia]

My 2¢ is that after many years using skylight filters I now don't bother, if you feel it affords you some protection fine, but really it is of no practical use.
Some cheap filters are coated on one side only, and therefore can reduce sharpness due to flare, in my opinion if you want to have some protection and actually reduce flare use a lens hood.

Sharpness is a bourgeois concept anyhow 

[DaveMiller]

I had made the assumption that we had enough gumption not to put a cheap filter on a quality lens, but it seems I may have been wrong to do so! It shouldn't need a magazine article to point out that is the wrong approach; or should it?

[Ken B: eyes, I just do eyes.]

This does the rounds quite often with people on both sides massing armies ready for an all out pre-emptive strike upon the other camp whop they consider - HERETICS!!

Consensus seems to be: If you are pixel/grain peeping then you can see a just barely perceptible softening, however since there is absolutely no application of a whole image where this BPS would be noticeable then it becomes a mute argument.

I have always used UV filters from day one, I have smacked them up, scratched, thrown them away when the got cleaning marks, they to me are disposable after a few years of use, the lens however has always had a crystal clear front element.

I had a drunken bride throw champagne at me, she slipped as I was about to take a photo and went a over T with ensuing results of flying drink, no time to clean, I just whipped the filter off, took a few frames, then retreated to clean and put the filter back on.

So my opinion has always been, there are far more pros than cons, so for £30.00 why not go for it?

[Mab]

I once had the Canon 35mm/1.8 LTM. What a beautiful little lens it was. Mine didn't didn't want to take any filter (or hood) and protested by vignetting so I finally let it go around naked.

[Francois]

It wouldn't even take a larger filter and a step-up ring?

[Ken B: eyes, I just do eyes.]

I once had the Canon 35mm/1.8 LTM. What a beautiful little lens it was. Mine didn't didn't want to take any filter (or hood) and protested by vignetting so I finally let it go around naked.

Mab, you owned a Canon, I am so sorry to hear this, you have utmost and sincere sympathy.


 

Well just got to be naughty occasionally   

[Late Developer]

I once had the Canon 35mm/1.8 LTM. What a beautiful little lens it was. Mine didn't didn't want to take any filter (or hood) and protested by vignetting so I finally let it go around naked.

Mab, you owned a Canon, I am so sorry to hear this, you have utmost and sincere sympathy.


 

Well just got to be naughty occasionally   

Now then......the Canon rangefinder lenses are not at all bad.

I have the Canon 35mm/f2.8 LTM (I can't afford a 35mm Summicron right now) and I cannot find a filter to fit it. 39mm is too small and 40.5mm is just too big. Apparently, Canon are one of the only manufacturers to specify a 40mm thread - or so I'm told. It doesn't sound like a difficult size but I have tried to find one. I think I'll have to see if there's a step up ring available.....