How important is UV/IR reduction in telephoto photography

BTW i typically use my 500mm F4.5 with its 1.4x TC 90% of the time.

Thanks

Lets here it experts, will IR blocking actually make for a sharper image as suggested in the general information on IR-cut filters? I'm pretty sure a decent UV will improve some contrast but is it enough? should i buy the combined filter with transmission compromises or should i make my own combination?

http://www.bhphotovideo.com/c/product/800660-REG/Heliopan_704678_46mm_Infrared_Blocking_Filter.html

This is the IR cut filter i'd consider in combination with the Hoya HD2 UV

Another question is since UV/IR all in one filters seem to have some compromises would it be stupid or smart to buy a UV filter and an IR-Cut filter remove the lock on the filter holding the glass in place, putting them flat against each other and re-locking them to act as 1 filter.

I think the most important thing to find out is will IR-Cut improve the images or should i not bother?

Basically i don't want to have to buy both to test them out and send one back. If you can give suggestions, or even possibly suggest something better that would be great

http://www.schneiderkreuznach.com/tipps/uv-ir_cut_filter.htm'>http://www.schneiderkreuznach.com/tipps/uv-ir_cut_filter.htm

P.S. here is the data on the B+W filter, stronger UV cut-off but notably lower transmission 88-89% range vs. the hoya with 97-98%

I know the Hoya tested well on lenstips site, i don't have a review on the B+W, I'm wondering if i should worry about the IR cut part of the B+W filter. Is it necessary for everyday nature photography? since it will be internal will any IR blockage(maybe reflection) cause the internal chamber of the lens to heat up a little? is it blocking IR light or IR heat from getting to the sensor? it suggest its ideal for CCDs but i'm using a CMOS.

or the B+W 46mm UV/IR Cut (486M) MRC Filter
http://www.bhphotovideo.com/c/product/154495-REG/B_W_65014686_46mm_486_Digital_UV_IR.html

The Hoya 46mm HD2 UV filter
http://www.bhphotovideo.com/c/product/900384-REG/Hoya_xhd2_46uv_46mm_HD2_UV_Filter.html

Now the 2 filters i'm looking at are...

The supplement
http://www.lenstip.com/120.1-article-UV_filters_test_-_supplement.html

The main article
http://www.lenstip.com/113.1-article-UV_filters_test.html

If you didn't know already lenstip.com has done an article and supplement article on UV filters, very technical and well done IMO.

I have a K-5 and a Sigma 500mm F4.5 EX DG lens which is great. someone on our forum recently bought one and after replacing the Sigma MC Normal filter with a high quality UV filter suggest he noticed improved contrast. Now i suspect there is a little of the placebo affect and new purchase must work affect happening but i am willing to also bet that there may be some improvement. In the desire to get the best results possible out of my most expensive lens I am considering UV filters, the lens takes 46mm drop in filters and i've located 2 that might be ideal.

however i do respect that there are legitimate reasons for UV filters and have a situation where i may consider it.

Now first and foremost i typically don't care to use a UV filter, i consider them a waste of money and i expect most of the cheap ones to degrade image quality and on top of that if one can't keep their front element safe then they're clumsy...

wouldn't mind you're opinion here, I asked this same question in the Nature photography forum but i know UV and IR blocking is important in astro photography too. One of you might have the answers i'm looking for.

Hey strangers

--
Mike from Canada
"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."
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