Infrared film images compared to digital IR

[mike_dodd]

Does anyone have any direct comparisons of IR film and digital of the

same scene? I have taken quite a number of IR images on film, see for

example:

 

http://www.amanita-photolibrary.co.uk/photo_library/BW_IR_sepia/index.htm

 

 

 

and I like the overall effect. I am now thinking of trying digital IR

using a modified camera (if I can get hold of one) as the IR digi

attempts so far with an eos300d were all failures e.g. central 'hot

spot', poor contrast and very long exposures. I am most interested in

how the digital camera compares with the large grain and halation of

the Kodak film which I like, in other instances digital 'grain' or

artefacts can look rather unnatural.

[mattb1]

I've only played around a little with digital IR and never with film. Digital IR is interesting and a little different than film I think. Out of the camera digital is all red, there are processing procedures which can give either B&W or false color images. I was never able to get IR out of my digital rebel, but it saved my old Minolta dimage from e-bay. Some cameras do not need modification beyond a IR filter.

 

Here are a couple of links with some great info: http://www.solev.net/

And http://www.jr-worldwi.de/photo/

[joseph_wisniewski]

You could try a Nikon D70. Unmodified, it doesn't have the speed of a modified camera, but it does have a lot better sensitivity than a 300D, and it's much more immune to center spots... (the 300D will improve markedly in this area if you use a simple prime, like a 50mm f1.8, instead of a zoom, especially the "kit lens").

 

Digital IR has no halation, and with a relatively sensitive camera (D70, or one of the modified Nikons or Canons) has essentially no grain. So you have to add some. Create halation using the "diffuse glow" filter in PhotoShop. Best way to add grain is by multiplying your picture by a scan of Kodak IR grain. Unfortunatly, the shots I've done that way are only viewable full size. The pics in my gallery are bigger than the ones in yours, but the downsizing still completly masked their grain.

[ranjith pallegama]

I have a very short but reasonably succesful results with digital IR.

 

http://www.photo.net/photodb/folder?folder_id=423990

 

I started with 10D which was a failure. Then I studied the subject and found out that different digital cameras have different sensitivities. Some cameras are not acceptable at all for digital IR. I used canon powershot G1 with success, and now using sony dsc-v3 with veryy good success. As matt told initial image has different tints, for some cameras it is red and for some others greenish etc. So these need considerebale amount of processing, and the easiest is to turn to grey scale. There are several photographers who post very good digital IR work on the PN, and the most significant is Tony

 

http://www.photo.net/shared/community-member?user_id=849714

 

He too use sony 717 and V3. After all Canon has released IR only camera 20Da and I do not know or I have not seen images produced by that camera.

 

Regards

 

Ranjith

[kelly_flanigan1]

Here is a mostly IR image. A 4x5 Phase One digital scan back was used on a Speed Graphic. NO IR filter was used. This allows both IR and Visible to reach the scan back. Without the filter; the scan is mostly IR; maybe 1/4 or less visible in energy. The lens is an ancient IR warrior used at F11. These once lived in bombers; P-51 fighters during WW2; looking to record those ball bearing factories as targets. These lenses are shunned by the LF crowd as being duds. They have radioactive high index glass. This is scan with the 178mm F2.5 aero ektar Kodak aerial camera lens. It is a decnt match for the 35 megapixel back.<BR><BR>This lenn was built in 1943; and bought surplus for 5 dollars. It has some separation and scratches too. If a retired Leica owner owned this lens; they would have a heart attack!. :) I suppose a new modern lens would be radically better; thus the peanut galley can buy me a better scan back :) :)<BR><BR>The buildings are 2.6 Kilometres from the camera. Some folks say this lens has laughable performance; and is not really a LF lens.<img src="http://i4.photobucket.com/albums/y148/ektar/scanback/SpeedGraphicF11AEsmall.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/SpeedGraphicF11AEmed.jpg"><BR><BR><img src="http://i4.photobucket.com/albums/y148/ektar/scanback/SpeedGraphicF11AEdetail.jpg">

[daviddbfotoart]

I just use the channel mixer in photoshop. Bump red up to +200, blue down to about -100 and hit the monochrome button. I've had some interesting results playing with this, may not be an answer to what u're after tho

[Brad_]

I've shot a ton of digital IR with a sony f707 and it works great. The nice thing about the

sony (f707/717/818) is that it has plenty of sensitivity for handhold shooting. And no

modifications are required, other than screwing an IR pass filter on the lens.<BR><P>

 

<a href="http://pages.sbcglobal.net/b-evans/Images9/IR_Web"><B>Some sony IR pix.</

B></a>

[mike_dodd]

Thanks for the replies, very interesting and helpful. However there are still a couple of questions.

 

From one of the suggested references it says that the sony can only be used at full aperture (f2.8) with IR which of course is no good for getting a decent depth of field and will have poor resolution on the edges of the image, is this true?

 

Second question is what causes the 'hot spots' in images taken on the 300d and similar cameras and whether they still occur on the modified versions of these cameras with the IR blocking filter removed. If it is something to do with the coatings of the zoom lenses (or the glass/plastic elements) then I assume the hotspots will still be there even with the filter removed and so even something like the d20a would be useless for normal subject IR with a canon zoom lens. This would be rather surprising as the leaflets that come with canon zooms do not say they can't be used with IR.

[ranjith pallegama]

Mike, as far as I know the hot spot is produced by the the long exposure time required by the digital SLRs. Do not forget that these cameras have a IR blocking filter to improve the quality of the normal images produced by the visible light. It is my experience that the faster canon lenses such as 50mm mark II produces no or at least negligible degree of hot spot. Please check my following images.

 

http://www.photo.net/photo/2711028

 

http://www.photo.net/photo/2711098

 

But still even these faster lenses require a quite a long exposure with higher ISO and the result is an image with higher degree of noise. There was a list of canon lenses that are acceptable to IR photography somewhere on the net, but I have lost the link. I hope somebody will post it here for the benefit of all.

 

Canon 20Da does not have the IR blocking filter as in the case of modified digital SLRs and takes only a fraction of a second to get an acceptable exposure, and hence does not produces the hot spot. I hope you can get this information verified by some other source too.

 

Ranjith

[joseph_wisniewski]

No disrespect to Ranjith, but center "hot spots" have nothing to do with time. There are two varieties. Sensor to lens to sensor reflections are a function of the shape of the rear elements of the lens and the IR reflectivity of the sensor (or its filter). Those are primarily seen Fuji and Kodak DSLRs.

 

Lens to lens reflections: those are mostly seen with complex zooms, although some simple priems have problems, too. Best thing to do is look for one of those lists that Ranjith mentioned. That's why his 50mm lenses don't have the problem: simplicity, not speed.

 

And in answer to your comment about the lens leaflets not mentioning IR, that's exactly it. They don't mention it, because it's not a concern to Canon. They don't mention that their film cameras fog IR film, either. And there are no IR focusing marks on their current lenses. IR isn't really a priority of theirs.

[ranjith pallegama]

Joseph, thanks for the facts that you have mentioned, and what I mentioned was something I had read somewhere. But, may be you are right; in that case, do you think that or have you any experience that even the 20Da or a modified DSLR (where the IR blocking filter is replaced by a another piece of glass with the same thickness) produce the hot spot with average zoom lenses? It will be very interesting to know. Thanks again

Ranjith

[frankl]

Hi Mike,

<P>

I've shot many thousand digital IR images and a dozen rolls of HIE over the past few years. I'm now using a Sony F828 camera to do my infrared and I wanted to clear up the misconception about the F2.0/F2.8 max aperature on the sony's. Yes sony has crippled the camera in some way, however because the camera uses a 2/3's sensor, the depth of field from F2.0 is still enormous because the lens focal length is actually 7mm at the 28mm equiv setting. Its actually more of a problem trying to isolate focus because everything is in focus.

<P>

There are lots of examples in the new gallery section of my website, <a href="http://www.abstrakt.org/">www.abstrakt.org</a>

<p>

Cheers,<br>

Frank.

[ranjith pallegama]

As I use Sony DSC-V3 I second Frank's words. If we calculate the depthe of feild with the known formulae it become from almost 1m to infenity.

 

Regards

 

Ranjith

[studiosix-o-three]

There was an excellent article about this in shutterbug a couple months back - if you have any access to back issues, i'd recommend getting your hands on it. the cover is of a little girl and a flower, and the main topic on the cover says something like "soft focus revisited". i'd be able to tell you more exactly what month, but i can't frickin' find it! hope this helps, cause it sure as heck helped me :)<div></div>