UV filters.

[glsammy]

I know there's been loads of comments before about the use of these, I've always smugly replied in the threads that I've always used cheap ones and I can see no difference.Now I've got a decent prime lens, I've discovered that the UV filter I'm using DOES affect the image quality. The seller has sent me a replacement to try, but that one is just as bad.
The problem shows itself in the out of focus background, especially when I shoot towards the sun. (Not directly at the sun I should hasten to add!) I get a very unpleasant streaking effect, almost as if the light is bouncing around creating double or even triple reflections.
Yesterday I was at Potteric Carr near Doncaster and whichever hide I was in it was directly facing the sun. I was shooting shots of a GSW when I noticed the unpleasant out of focus effect. I took off the UV and the streaking was gone.
Because of the design of the hood on my lens I think this 300mm lens will be one I'll take a chance and not use a UV filter. I don't want to buy a top quality one and still see the problem!
I was going to load a couple of shot to show, but I was so fed up with yesterdays efforts I deleted the lot.

[Gaza]

Good point glsammy
I have read many a point of view, as to whether UV filters should or should not be used

Main reason for not using them ( that i have read ) is, that anything that is put in front of the lens, has to, even if only slightly, cause loss of image quality.

I have always used them, for the sole purpose of protecting my lens
But reading your post, i may try a few shot's with and without, to see if i can see a difference

[glsammy]

Originally Posted by Gaza

Good point glsammy
I have read many a point of view, as to whether UV filters should or should not be used

Main reason for not using them ( that i have read ) is, that anything that is put in front of the lens, has to, even if only slightly, cause loss of image quality.

I have always used them, for the sole purpose of protecting my lens
But reading your post, i may try a few shot's with and without, to see if i can see a difference

Yep, I've always used them for protection. However, the lens hood doesn't come off on the 300mm so there's less chance of damage. If I hadn't seen this effect on the image I certainly would be using one. I once found a small chip right in the centre of one of my UV filters, how I did it I don't know, but I was glad it was the filter that was damaged and not the lens. If the filter degrades the image, then I wont use it.

Try a shot shooting a subject with the light in front of you, making the subject backlit. This is when I noticed the problem. Almost every shot I took yesterday had this effect on it. Editing can remove it, and the in focus part was fine, but it does make me wonder if it degrades the image in any other way.

I'll have to try and recover some of my shots from yesterday to highlight exactly what I was seeing.

[zan]

I've noticed the same thing I quite happily used a UV filter with my first cheapy 70-300mm Sigma zoom, then switched to the Canon 300mm F4 prime and the difference was so noticeable when I had the filter off I've never used one since! I use the hood to protect the front element, and that does perfectly.

[glsammy]

I've managed to recover a couple of shots that show the problem nicely.

Here's the first shot with the UV filter fitted:



The very next shot, with UV Filter removed:



Both shot @ F8.0.
Don't forget we're only looking at the out of focus background, not the quality of the rest of the shot,(Or the lack of it!)

[Gaza]

Can't argue with that. glsammy
Quite a lot of difference, Cant say I'd ever noticed it in my photo's
But i will be looking now, and going to try some shots with and without the filter, when i see a little bit of sun

[Meta menardi]

I shall have to check that, half the time I don't notice the quality issues people mention ( quite pleased I can see anything), but that is noticeable.