Lenses for IR (FF)

[LongLensPhotography]

I've tried doing some IR work with R72 type filter and my trusty 1Ds2.

The results are interesting and I love the added ND 12 stop effect, but there is something wrong with resolution anywhere but the centre of the full frame (anything larger than A4 would be dead obvious).

17-40mm has really poor edges and midframe in IR mode at f/16; 24-70mm is probably worse! Both perform really well without the filter; and yes, I've used IR focusing marks.

Perhaps as zooms they are made very complicated and not optimised for IR. Are there any MF wide primes that perform really well normally, and create just as sharp IR images? I might one day get 24 TSE or Zeiss 18 / 21mm so would be interested to get some idea as well.

Or should I not use FF camera, but something APS-C? (just so I know, very unlikely to buy one)


Clifton IR-scape

17mm 138s ISO100 focus somewhere between 1m and inf.

 

[HoppyUK]

It's well known that some lenses perform better than others for IR, with hot-spots and so on, though there don't appear tio be any rules.

I have no personal knowledge, but a quick google threw up this list http://dpanswers.com/content/irphoto_lenses.php

 

[LongLensPhotography]

It's well known that some lenses perform better than others for IR, with hot-spots and so on, though there don't appear tio be any rules.

I have no personal knowledge, but a quick google threw up this list http://dpanswers.com/content/irphoto_lenses.php

Thanks, but I don't think it touches on my question :shrug:. Hotspot is the last of my worries now and can be sort of fixed easily in post.

 

[HoppyUK]

Thanks, but I don't think it touches on my question :shrug:. Hotspot is the last of my worries now and can be sort of fixed easily in post.

IR and high levels of sharpness tend not to go together, but the point is really that some optical glass behaves differently at IR frequencies and it's impossible to know what works best without trying it. It's unrelated to lens type or design, just the particular glass used.

The info must be out there somewhere if you google around.