Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: dchew on April 27, 2014, 08:30:08 am

Title: 35mm for a Canon 5DII IR Conversion
Post by: dchew on April 27, 2014, 08:30:08 am

I just had my 5DII converted, and sent a Zeiss 35mm ZE with it for calibration. They called to tell me that when they tried the lens it showed a pretty strong hot spot.

So I'm looking for a 35mm lens in a Canon mount that plays nicely with IR. Any suggestions?

Image quality is most important, but I will usually be stopped down at least to f/4

Don't care if it is manual focus or auto, but I would prefer manual. I will be using it on a tripod with live view so I like the longer helical rotation of a manual focus lens.

Speed is not important. In fact I'd rather save weight with an f/2 vs 1.4

Price not important (no Cooke though!!)

Dave

Title: Re: 35mm for a Canon 5DII IR Conversion
Post by: Herbc on April 27, 2014, 10:58:42 am

You might try it yourself.  I had a similar response from LifePixel when they converted an A7r.  On further testing, I found the hotspot they spoke of was at f22!!  Way beyond the beginning of diffraction.
I tested the lens myself, and found no hotspots from f2.8 thru f11, which is about all I would use anyway.

On another side, I had a hotspot show up in an IR photo that I put to advantage, won a prize or two with the photo- people think it is the sun.  That was in a Canon 50d IR camera.

Title: Re: 35mm for a Canon 5DII IR Conversion
Post by: Robert DeCandido PhD on April 27, 2014, 05:04:32 pm

the Canon 24-105 F4 is fine in IR...I have a converted to IR 5D2 - and no hot spots with that lens...at least to F11 (I don't shoot beyond F11). The Tamron 24-70 F2.8 IS also is fine - no hot spot at least to F11).

There is a thread over at FM forums where user "Burningheart" tested a number (at least 30 if not 50) of lenses on Canon converted to IR bodies (5D2 if I remember well). I believe it was in 2011 or 2012..you might do a search for that thread if you are specifically looking for a 35mm lens to use on a IR 5D2.

Here is some IR work in Central Park: http://photo.net/photodb/folder?folder_id=637107

and along the Bronx River: http://photo.net/photodb/folder?folder_id=399445

Title: Re: 35mm for a Canon 5DII IR Conversion
Post by: dchew on April 28, 2014, 06:13:45 pm

Thanks guys. Herb, great point; I will certainly evaluate the lens myself, and it is indeed LifePixel who did the conversion.

Robert, great images! I will check out Burningheart's post.

Ciao,
Dave

Title: Re: 35mm for a Canon 5DII IR Conversion
Post by: joneil on May 02, 2014, 08:46:34 am

I will chime in and say also judge the lens for yourself, not what others say.  When I had my Nikon D7000 converted to IR, all the internet "experts" told me my old manual focus 24mm F2.8 was a poor lens because of a "hot spot".

The only hot spot I ever found was when I shoot into the sun, otherwise I think it is a great lens.

So test it extensively for yourself before you spend any more money on another lens, then decide.

good luck