sigma 150x500 filter?

[sparky]

My question is,do I need to use a filter on my lens? if so, what would be the one to get?and for what effect if any,? or to protect the lens itself,??
I use the lens only for wild life,well and the camera
any addvice would be helpfull,
thanks for looking in,all the best Ian...

[postcardcv]

There are two reasons to use filters - firstly for the effects that they give and secondly a protection for the front element of the lens. If you want a photographic effect that a specific filter will give then it is clearly worth using one. However whether it is worth fitting a UV filter purely for protection is another matter. Some people always fit protective filters, personally I never do. I tested some filters on my lenses and found that they had a detrimental effect on the image quality, this seemed more pronounced at longer focal lengths. So I don't use them and rely on the lens hood to protect the front elements from getting knocked.

[sparky]

Originally Posted by postcardcv

There are two reasons to use filters - firstly for the effects that they give and secondly a protection for the front element of the lens. If you want a photographic effect that a specific filter will give then it is clearly worth using one. However whether it is worth fitting a UV filter purely for protection is another matter. Some people always fit protective filters, personally I never do. I tested some filters on my lenses and found that they had a detrimental effect on the image quality, this seemed more pronounced at longer focal lengths. So I don't use them and rely on the lens hood to protect the front elements from getting knocked.

thanks posty,that'll do me boy,you just saved me a few quid,

[miketoll]

I remember when my then very young son put a liberal coating of jam all over the front of every lens I then owned and I was glad I had UV filters on them all as it meant I could just take the filters off and wash them which was the only way I could deal with the jam. Try that with the lens itself.

[postcardcv]

Originally Posted by miketoll

I remember when my then very young son put a liberal coating of jam all over the front of every lens I then owned and I was glad I had UV filters on them all as it meant I could just take the filters off and wash them which was the only way I could deal with the jam. Try that with the lens itself.

it's not enough to convince me to use filters, but I will be putting the jam on a higher shelf

[yelvertoft]

Originally Posted by miketoll

I could just take the filters off and wash them which was the only way I could deal with the jam. Try that with the lens itself.

As my most expensive lens is waterproof, it wouldn't be an issue for me, I'd run the whole lot under a tap.

Like Peter, I used to use UV filters to protect the front element when I used film cameras. When I went to digital, I used the new lens without a filter fitted as I didn't have one of the right thread size. When I did then buy one, and fitted it, I realised just how much it was degrading the image. Took it of and haven't used them since.

The people in shops will tell you it's essential to have a UV filter to protect the front element. I rather think this advice is based on boosting sales of accessories.

[Roy C]

From my experience filters degrade the image quite a lot on long telephotos whereas the same filter on a wide/normal lens does not seem to make that much effect. That's certainly what I have experienced with the 400/5.6 and 17-40/4 when using the same filter.

[Joe]

Any filter is going to degrade the image you get from your lens. It's just a question of weighing up to pros and cons of fitting filters and which one you use/ how much degredation you can stomach. I've been using B&W or none at all. Some lenses are worse than others when fitted with protective filters. My Sigma 15-30mm is simply (more) terrible with anything fitted (probably due to the poor filter ring/hood arrangement), Nikkor 80-200mm is passable......
One thing to mention about protective filters.... They do protect against other things not just rain. A lovely lens in the shop, looked after, except for a ruddy great scratch across the front element from suspected mud/grit. However, it never fails to amaze the number of top-notch Canon L and Nikon AF-S expensive glass seen with the cheapest Chinese filters screwed to the front!...So, I can see both sides of the 'for and against' can come into play.
I guess the key factor is to decide the as and when to use lens protection, rather than to fit and forget.

[Roy C]

I have now got a Canon 300/2.8 so I no longer have to weigh up the pros and cons of a protective filter - you cannot fit one if you wanted to.