need help w/ infrared

[Efergoh]

I am taking a landscape photography class, and we are taking a trip to Maine for the first week of June to take photos.

I am taking 3 cameras with me, a 35mm film slr, my DSLR, and a Deerdorf 8x10. Along with 100 sheets of 8x10 film, I also purchased a box of infrared 8x10 for the trip.

I've never shot IR film before, so I need a bit of help with how to focus and expose. The film I've purchased is Efke 820.
I have a red filter already as I sometimes shoot B&W through a red filter, but any help, advise, or links would be greatly appreciated.

 

[Efergoh]

guess I'm on my own, eh?

 

[Helen B]

What sort of bellows does your Deardorff have? If they are leather you may need to cover the camera with something that is opaque to IR before you pull the darkslide. Similarly you need to use an IR-proof changing bag or tent for loading the film holders - most cloth tents and bags are opaque to IR, my Harrison certainly is.

If you have time (running out) run some exposure tests with the 35 mm version of the film you are using. I have used Efke 820 with a B+W 092 filter, rated at EI 6, with the meter reading taken without a filter. If you are using a Wratten 25 or a 29, or a B+W 090 or 091 you could increase the EI a little.

For focusing the usual practice is to rack out by f/250 after focusing visually - ie just a tad over a millimeter for a 300 mm lens. In practice if you are only using a red filter this may not be necessary, especially if you are able to focus with the red filter in place. The amount and direction of adjustment is not fixed - it varies from lens to lens - but a slight increase is common. What lens(es) do you have?

Best,
Helen

 

[Efergoh]

just one lens...300mm.

The bellows aren't leather, but I'll put the changing bag over the bellows when I shoot. I know that is IR proof.

My filter is a red 67. I have it taped to the rear of the lens. I couldn't find a filter large enough for the front, and the threads on the rear are too fine for the filter, so I held it in place and taped it on with gaffer's tape. Works just fine when I shoot B&W.

I'll see about getting some 35mm efke, but I had to mail order the 8x10. I don't expect to find it local. My professor said something about having a good bit of 4x5 efke, and I do have a reducing back for the deerdorf, so I'll see if I can't pandhandle a few sheets from him.
Time is indeed short, we leave at 6am on the 1st.

 

[Rhys]

Just meter for 100iso visible light. Focus for normal light and then if there's a red dot on the lens, adjust focus back toward the red dot. That's all there is to it, really.

 

[Helen B]

Just meter for 100iso visible light. Focus for normal light and then if there's a red dot on the lens, adjust focus back toward the red dot. That's all there is to it, really.

Just for clarity, I'm guessing that you are referring to the setting for a meter that is behind the filter or for an unfiltered meter before a filter factor has been applied - hence the discrepancy between our suggestions. EI 100 for an unfiltered meter seems very high for Efke 820 even with only a red filter on the camera. I used EI 3 to 6, (unfiltered meter) albeit with IR filters on the camera. For a red 25 I would have thought that EI 12 to 25 was closer to the mark than 100 (all with an unfiltered meter).

The Deardorff is a large format camera. The lenses used with that type of large format camera do not usually have focusing mounts - the camera itself has the focusing movement, so it is not possible to have a 'red dot', unless you put one on yourself for a particular lens - you would have to know where to put it, of course.

Efergoh,

Could you get a Lee polyester IR filter for your lens? Maybe you could get it shipped directly to Maine. If I can help, let me know. B&H is a short walk from here, and they are open today and tomorrow.

Best,
Helen

 

[Rhys]

The largest camera I used was a Linhof 5x4. I used to use Kodak infrared 35mm in my Nikon FM. Then I metered for 100ASA and put a red filter on the lens after metering. My photos came out well enough - even when I forgot to use the red dot.

 

[Alpha]

In my experience, Efke IR is sharp enough at visible focus if you're using a 25 or 29. Any filter more opaque and you'll definitely want to adjust focus.

 

[Efergoh]

Efergoh,

Could you get a Lee polyester IR filter for your lens? Maybe you could get it shipped directly to Maine. If I can help, let me know. B&H is a short walk from here, and they are open today and tomorrow.

Best,
Helen

I'm going to make the drive to the camera store tomorrow (nearest one is a 45 minute drive) and see if they, by chance have one. I don' have high hopes, but I need a step down adapter anyway, so I'm going to make the drive.

Thanks for the offer, but where I will be is a bit outside of civilization. What I have is what I have. I only have 10 sheets of IR anyway.

My professor suggested that I meter for 25 ISO. Most of my shots will be at f96, and focused to infinity, but some might be closer.

 

[Efergoh]

Well, I shot my IR film....

I metered for 25 ISO, but neglected to count for the filter, so it was underexposed by 3 stops, so I had to push develop the film, and didn't get any IR effect on any of it save for one sheet that I double exposed.

Turns out Efke does not recommend a 25A filter for their IR film...bollix!

Oh well, lesson learned. I still have two sheets left, I'm going to use deeper red filter and see how it works out.