I'm looking for a little expert advice.
I have a Nikon 300MM F4 on my D300. It's rock solid and tack sharp...Without a filter on the front.
I bought a Tiffen Digital HT Ultra Clear filter. It's an expensive clear filter that when I look through it is... Crystal clear. But, every image I take with it is very soft. Not just a little back or front focus, but a terrible looking, out of focus shot.
Any thoughts on what would cause this ?
Adding any glass to the optical path will have an impact. The lens was engineered to perform with "X" amount of elements.
Unless shooting in blowing sand, salt spray, ground level motocross rooster-tails etc.... just use your hood.
I think that your filter may be warped and therefore causing some weird image problems. It is true that even a good filter will alter the optical engineering a bad quality filter can really screw it up. That's why i decided to invest in B+W filters on the lenses that i use the most and I have Hoya HMC filters on lesser used lenses. I used to have some Tiffen UV filters and had nothing but problems with them, additional flare, breaking when being installed on lens thread, etc. Only Tiffen things I have now are CPs which I don't feel there is a need to invest in good ones considering how rarely I use them (haven't used one in at least 3 months). I recommend trying it with a B+W filter, that should solve your problem.
A defective filter can be loose within the filter ring and cause some image softness due to the filter element moving. Not common but it happens occasionally.
Other than that, if the filter is uncoated or poorly coated on the lens side then it can introduce additional reflections that contribute to ghosting or flare on the image sensor. I don't know what coatings your filter has.
Also, if you feel the filter is truly causing a problem, simply ask the manufacturer for a replacement under warranty. Or if you prefer to go the retailer route, and you bought the filter very recently, you may be able to return or exchange with directly with the retailer at which you bought it.
I almost never use filters on lenses, except a polarizer when needed. They have a way of causing me problems. When I buy a lens on eBay and it comes with a filter on it, I throw the filter away first thing. I do use the tough lens cap to protect my glass though, and lens hood. My lenses are perfect.
Even the very best filter is going to add 2 air to glass surfaces for the light to go thru, multicoating helps, but there will be light losses and reflections. Tiffen is probably the worst I've seen, Hoya is better for the money, Nikon, Heliopan and B+W are the best. Sounds like you got a really bad filter, the worst I've seen so far is an overall softness with lack of contrast. I met a guy years back who was selling a 300 f4 (early AF). I put the lens on my F5 (yes, I said it was years back!) and the image was horrid, soft, milky and lacking contrast and snap. I looked at the front of the lens and low and behold, a clear filter (Tiffen at that!). I removed the filter, image quality improved dramatically. I showed the seller, he was amazed. The lens was a little more beat up than I wanted and now that it seemed sharper, he decided to keep it.
I prefer to use a lens hood for protection in all but the worst conditions, when I use a Nikon L1bc.
For well over a decade now, I've been using the best Hoya and B+W UV's on the end's of the best glass I could buy. I've NEVER (and I do mean NEVER) gotten a shot with lowered IQ as a result of this behavior. I've read reports and reviews of others that have had all kinds of issues with use of filters on the end of good or great glass. The theories abound, and while they may seem to make perfect sense, try as I may, I've tested and worked with many and have never gotten ANY loss of sharpness, contrast or flare from using them. Either my angle of incidence has been perfect to avoid these issues, or I'm just sticking with good filters overall. Ya'll can argue this till the cows come home. If you are paranoid about using a quality filter don't. That simple. As for "assuming" it will "automatically" reduce the IQ please spare me the diatribe. Been there done that. Not interested. It makes about as much sense as assuming if you don't get the swine flu shot you are doomed. I won't bore you with the argumentative details regarding the OTHER end of those that subject themselves to being medical experiments in the grand scheme of the medical and political world. I just wish this whole filter vs. no filter argument would die, but it keeps getting life, and the passionate arguments continue on both sides. I'm a protectionist believer. Hoods are fine for obvious obstructive damage, but do next to NOTHING for environmental intrusion. Be it dust, general schmutz or whatever. You can do as you wish. I've made my decision and it serves me just fine.
Shooting with a "clear" filter is like shooting through a window. Unless you're shooting in the desert, I'd take full advantage of the wonderful glass that Nikon makes and leave it off. It's like the friends of my parents that always had a plastic cover on their expensive couch.
I've shot Canons, Nikons, Leicas and Hasselblads for 35 years and never had a problem for lack of a "clear" filter.
Thanks for the great feedback, It's definitely the filter. I took some more shots with it today in bright sunlight, setup on a tripod. I was in a garage well back from the direct sun and shooting out into the sunlight (Sun was behind me)
I did a series of three test. One set without the filter, one with the filter and one without the filter, but a clear piece of single pane window type glass pressed flush to the end of the lens (Not touching...Just pressed against the ring)
The test without the filter and with the plain piece of glass looked great, the one with the filter looked terrible.
I'm still shaking my head... It must be the special super duper coating that is screwing it up.
I've called tiffen and sent a email, but have not heard back.
billkoe wrote:
Shooting with a "clear" filter is like shooting through a window. Unless you're shooting in the desert, I'd take full advantage of the wonderful glass that Nikon makes and leave it off. It's like the friends of my parents that always had a plastic cover on their expensive couch.
I've shot Canons, Nikons, Leicas and Hasselblads for 35 years and never had a problem for lack of a "clear" filter.
A quality filter is nothing like a window, if by which you mean the kind found in a house. That glass is produced by floating molten glass on a bath of molten metal.
I have Canon Protect filters on a couple of lenses and a spotting scope and tests showed no detectable impact on resolution and contrast when used on a D200, although there is bound to be an increased tendency to flare in certain circumstances. I have not tested on FX, so for me that remains unknown.
I think the main advantage of filters is that if you buy a lens which has always had a filter on it, the chances are the owner has never touched the lens's front element, but has probably abused the filter e.g. using a cloth or even a hankie to 'clean' the filter glass.
trenchmonkey wrote:
Adding any glass to the optical path will have an impact. The lens was engineered to perform with "X" amount of elements.
Unless shooting in blowing sand, salt spray, ground level motocross rooster-tails etc.... just use your hood.
That filter thread at the front of the lens.. what do you think it's there for?
Elan II wrote:
That filter thread at the front of the lens.. what do you think it's there for?
Graduated ND's, ND's, color filters, polarizers, warming filters, cooling filters, infrared filters... lots of choices out there. Absurd to imply that a UV filter should be there just because there's a ring there. Or perhaps you were not aware of all those other uses for that ring?
The use of a filter is particularly problematic on a long lens. The narrow field of view causes light rays reflected out of the camera/lens to be reflected straight back from the flat surface from the filter onto the lens elements and the sensor . This is most clearly seen on my 70-200 with a filter as lost contrast. And I use high quality multi-coated B&W filters.
trenchmonkey wrote:
Cir Pols when the situation calls for it, smart ass.
Firmly agree with my simian friend above on this one. A few months ago I figured up the finanacial risk/benefit on so-called "protection" filters. I checked with two Nikon repair places and found that a front element replacement would run about $225. For me to put high quality (e.g. B+W) MC filters on my five most used lenses would run me close to $375 (B&H price.) Thus it would cost me more to buy the filters than it would to pay for a hypothetical repair. This made no sense to me at all. Like the monkey, I am almost totally an outdoor photographer, usually in harsh Dakota conditions. I don't routinely use filters; my lenses are all perfect. Modern Nikon coatings are very, very durable unlike Nikon's earlier ones. This is sort of like a religion: a strong belief based on faith and not evidence, so I'll leave it alone.
I'll will mention that on other forums in the past I've seen more complaints about Tiffen brand than any other. As with most things in photography, when you try to go cheap with optics, there can sometimes be a cost.
