Darn hotspots!

[groovyone]

My 24-70Z works very well for IR, most of the time. I cannot figure out why I occasionally get hotspots with it, and the conditions do not seem to be consistent.

Anyway, here are a few shots from Colorado I liked, except for the dang hotspots. I got some without, but it bugs me the most on this one.

DSLR-A100IR - 24-70@24mm - f/11 - ISO100 - 1/10s


DSLR-A100IR - 24-70@24mm - f/11 - ISO100 - 1/25s


DSLR-A100IR - 24-70@24mm - f/6.3 - ISO200 - 1/250s


DSLR-A100IR - 24-70@24mm - f/6.3 - ISO200 - 1/250s


DSLR-A100IR - 24-70@26mm - f/5.6 - ISO200 - 1/400s


DSLR-A100IR - 24-70@24mm - f/5.6 - ISO200 - 1/320s

[tc95]

What is your shutter speed...f-stop...and exposure...for these...

[tc95]

Here are some fixes I did quickly...to try to cover up the Hot-Spots...hope this helps you out...













Sorry in advance for just pulling them and working on them w/o your permission....but again hope this helps out a little...

[groovyone]

I don't mind. INteresting edits. I have found that I can hide the hotspots pretty well with B&W, but lately I have been so busy my IRs get one edit, maybe. hah

I did do a lake pano in a blue tint that I liked:

[bburton]

Hotspots: the bane of the IR photographer -- along with noise, of course. I hate them. My usual approach to hotspot removal:

(1.) In Photoshop, use the eliptical marquee tool to encircle generously the hotspot.
(2.) Select "Feather" with a radius of 200 pixels.
(3.) Adjust "brightness" lower by eye to match the rest of the photo.
(4.) Repeat with a smaller circle of the eliptical marquee tool if needed.

Note: Often, the only way to redeem an IR shot with a strong hotspot is to convert it to B&W and boost the contrast generously.

[jeffkohn]

My 24-70 is the same way, I don't use it for IR anymore. I'm not sure, but it seemed to be a combination of focal length and aperture that determined how bad it was. (And of course composition, since the hots spots are much more noticeable in a dark, uniform area such as sky or water).

[jerrykr]

Try, all of the aperture settings for the same scene as a test. I believe that you will have less hot spotting with smaller aperture settings. Every lens is different, but it's worth a few test shots to find the best setting for your lens.

[jeffkohn]

According to Lloyd Chambers, some of the Ziess ZF lenses have hotspots at small apertures but not large. I haven't tested to see if it's the same case with my 24-70, though. (And honestly I don't have much need to now that I've gotten the 16-85VR).

[groovyone]

Updated the first post with EXIF info. Didn't realize my shutter speeds were so low on the first two, but the ones after that were primarily shot in M, not sure why I ventured up to ISO200. These are a month and a half or so old already.

[jblaschke]

Good luck with your investigations. I've given up trying to figure out the cause of the random hotspots with my 28-135. I'm wondering now if it's temperature related. I seem to recall that all the shots I took with hotspot problems were done during the winter months. Granted, none of them were below freezing, but I don't think I've ever had a hotspot when shooting during warm weather...