Focus and an IR modded camera

swag72

swag72

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I'm sure that I already know the answer to this, but just thought I'd ask and see your ideas / comments.

I was out yesterday with my IR modded 10D. I bought it already modded.

Yesterday was really only the second time out with it, so I thought I'd have a play with some landscapy stuff. I was using my 24-70 at f/8, this is a crackingly sharp lens on my 5D2. I found when I got home that the pics were really soft. They were taken in raw, so withstood some sharpening without too much issue.

I guess my biggest surprise was the lack of sharpness compared to the same lens on a different camera. I have played with the focus today, and it just doesn't seem well focusing at all.

Would the IR modification affect focus at all? I am assuming not. Perhaps the 10D focus is just a little old and tired? Middle focus point used.
 
So, if I contact the company that did it - They will be able to help with that?

I'm assuming that the focus was right for the previous owner - Can it lose focus over time?
 
swag72 said:
So, if I contact the company that did it - They will be able to help with that?

I'm assuming that the focus was right for the previous owner - Can it lose focus over time?
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If it's right it's right, if you see what I mean. It may well be that it wasn't correctly setup in the first place. When I did my D70s it was "near enough" but it'll vary from body to body.

On Nikons it's very easy to adjust the focus of the body, all that's reuired is an allen key, but I'm not sure if the same applies to Canon.

If it does then it's a straightforward diy job, it just means taking a shot, doing a wee bit of adjustment, another shot, another tweak, until you feel it's right. There's probably pro equipment available to set it up with 100% accuracy but that would cost money :nono:
 
swag72 said:
Where's the allen go? and how do you adjust?
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On the Nikon bodies the adjustment screw is on the rh side of the camera as you look into the lens mount, behind the mirror.

Adjusting it is just trial and error, turning the screw either clockwise or anti-clockwise and taking a test picture to determine if it's better or worse.
 
Also it is worth bearing in mind that once an IR camera has been optimised for a particular lens (or lens range) it will probably not focus that well with other lenses. For instance, my D80 IR (after a few goes) focuses perfectly with lenses from about 16mm focal length upwards but will not focus at all with 10-20s, 12-24s etc (due to them being highly retrofocal, I have been told). You sort of have to decide which focal length is most useful to you and stick with it. or get a second camera converted, of course.
 
I am happy if I can get a pretty sharp focus on my 24-70. I have googled, but can not find anything relating to how I may go about this :help:
 
If you can't find info on how to do this yourself you could try sending it to Advance Camera Services (ACS) - they are specialists in IR conversions.
 
I've already spoken to them as they did the original conversion - confirmed through serial number - They said that there is no reason that the focus should change.

Here's a screen grab that I've just done - linky - Taken with my 24-70 at f2.8 at 24mm. jpeg and no PP, beanbag rest and timer. While it doesn't look as though there's back / front focusing, I just don't think it looks particularly sharp.

Would welcome your thoughts on this.
 
With all the older lens on film body's you had a red line that was next to the normal line to set your focus onto unlike modern lens.
As with all wave lengths they all focus at a different point, the IR being much farther out then white light (which is all the visible colours )
 
swag72 said:
I've already spoken to them as they did the original conversion - confirmed through serial number - They said that there is no reason that the focus should change.

Here's a screen grab that I've just done - linky - Taken with my 24-70 at f2.8 at 24mm. jpeg and no PP, beanbag rest and timer. While it doesn't look as though there's back / front focusing, I just don't think it looks particularly sharp.

Would welcome your thoughts on this.
Click to expand...
The focus does appear to be a bit out and it doesn't look like anything is in focus - the same problem I had with their conversion initially. Have you tried sending them the body with the lens that you intend to use with the body most often? It took them a couple of goes to get it right with me and once the focus was correct with that lens it worked with others within the same focal range.
 
I have spoken with them and will send it if needed. I tried a couple of pics today, with the 24-70 and the 50, just incase it was the lens, as they had initially suggested.

Didn't seem to make much difference really.

I'm glad that you have concurred with my thoughts Paul.
 
Another thing that occurs to me is that the sharpness of an infrared shot seems to depend on the "quality" of infrared light. I have had many instances of taking IR shots when overcast and finding the image very soft and then shooting at the same place later in the day, when the sun has come out, and finding the shot much sharper. Sometimes it seems as if there isn't enough infrared light for the camera to focus properly. However, given that you are in Spain and there seems to be strong sunlight coming through the window, I don't think that this is the case here.
 
Enjoy the trip! Spain can be a great place for IR photography especially if there are one or two clouds in the sky to provide a bit of contrast. I often find that the Spanish are nice enough to plant a few cacti in front of their churches that give IR pictures a great contrast between the building materials of the church and the glow of the plants.
 
Actually, many IR conversions are converted to be used with one specific lens. When I had a Canon D60 converted, I sent my 50mm f/1.8 lens in with the camera for calibration. The guy who did the conversiion recommended that if I use any other lens that I should keep the f/stop at f/11 or smaller.

I really wish that I converted a P&S camera instead of the D60. I am traveling to China in April and would love to get some IR images but, don't want to carry the weight of a third full size camera (I am shooting China with a Canon 30D and a 40D). I could just slip a P&S into my shooting vest and pull it out when I want IR images.
 
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