Konica 750 Infrared & RZ 67

[joseph_e._forks]

Hey Guys,

I'm going to the Grand Canyon Saturday with my RZ and a

good friend gave me a bunch of Konica 750 Infrared.

 

I've read every thread I could find on this site in regards to

my subject and found some good information, so I just want to run

this by you guys and make sure I'm on the right track.

 

I'm going to buy a filter today or tomorrow, probably a Hoya Red

25A, or Maybe an Orange YA2. Do you have a personal subjective

preference between these two filters and the end result?

 

The base ISO for this film is 32 and if I run it through the Red

25A filter I should run it at ISO 16, is this correct? Same exposure

for the Orange YA2? I have enough film that I can afford to bracket

heavily, and so I will do that.

 

Maybe I should try some without a filter as this film is supposed

to have excellent gray tonal quality?

 

Lastly, I'll be using a 50mm ULD and an older model 65mm, stopped

down significantly so I'm hoping I don't have any issues with

focusing the IR film. Should I be concerned with a focusing issue

using these parameters? The posted info on this is confusing and

somewhat contradictory at best.

 

Thanks for any and all insight.

 

Best regards

Joe Forks

[geoff_mcauliffe]

I have used Konica IR in a Yashica TLR with excellent results. I exposed at 1/8 or 1/15 at f11 with either a red (25A) or an orange (15) filter, and developed in Rodinal 1:50 for 7.5 min at 23 degrees C. I found no difference between the red and orange filters. Keep in mind that the amount of IR you encounter in northern AZ will probably a lot more than what I had in central New Jersey so bracketing will be needed. I don't know where you got the idea that the film has "excellent gray tonality", maybe so without a filter. With a filter the film is very contrasty, that is why most users suggest Rodinal 1:50 for development. Visit Ben Kreunen's website for his beautiful results and processing recommendations. Finally, there is no need to worry about focus shift with this film. Good luck!

[joseph_e._forks]

<B>I don't know where you got the idea that the film has "excellent gray tonality", maybe so without a filter.</B>

 

Yes, w/o a filter, and it's just something I read as I have no experience with this film. I appreciate your responce very much!

 

best

Joe

[josphy]

Just to confirm something you said, Joseph -- I have shot this film quite a bit at both 32 without the filter and 16 with the filter, and my exposures have pretty much always been spot-on. (That's using an incident light meter without the filter over it of course). I guess I should say that is also in bright to fairly bright sunlight.

 

Anyway, I really like this film a lot because I've gotten such consistent and excellent results from it right from the very first time I tried it. I develop it in D76 for (I think) 6 minutes -- whatever the manufacturer's recommended time is -- and that always works out perfect. Bear in mind that you won't get mind-blowing IR effects with only a red filter, but it's still very nice. My next purchase is going to be an 89B or 89B-equivalent filter. If you wanna see some examples, you can check out http://www.geocities.com/josphy All of the photos on there were shot with Konica IR 750 in an old folding camera.

 

Oh, I just noticed some more of your questions...I would go ahead and get the Red 25 filter. This film has some sensitivity to blue and green I think and then starts being sensitive again in the red and near infrared spectrum, so if I'm remembering this all correctly, I think orange and red should actually have the same effect, but I would just go for red. A dark red would give stronger effect (Red 29). Best of all would be an 89B or Hoya's equivalent which is called RM72 I think. You can also get the Ilford SFX filter which is available as a gel filter or for Cokin filters -- it's the equivalent of an 89B but only costs about $10-15. But, for starters, go for the Red 25 and just get some experience with infrared, and then later if you decide you like it, you could spring for the stronger true infrared filters.

[joseph_e._forks]

That information is greatly appreciated.

 

I had to take what I could get locally in the way of filters for this trip and settled on a dark red R2, which was the only red in stock at the moment. Hopefully that will do the trick.

 

I'll be real happy if I can get some exposures like your samples at the Grand canyon, so thank you for that confirmation on ISO. I'll be

sure to bracket liberally as well.

 

Are you in Austin Joseph? If so I'm right down the road from you in San Antonio. I'll be sure to share some samples with the forum when I return.

 

best regards

Joe

[josphy]

Yes, I am in Austin, Joseph. You might want to bracket somewhat if there are some once-in-a-lifetime photos opportunities, but as I said before, I have had amazingly consistent results with Konica. If you get a chance, just fire off one roll before you leave for your trip and bracket around and EI of 16, and I bet you are very pleased with the results. One thing I like about infrared is that you can shoot in really sunny, mid-day conditions that you probably wouldn't want to shoot regular film because of the contrast. Anyway, definitely post some results or feel free to email me directly.

[josphy]

By the way, is that dark red R2 filter the equivalent of the Red 29 ? I'm not sure what the R2 you mentioned is equivalent to, but, if it's the same as a 29 you might want to base your exposures on an EI of 12 instead of 16 since the Red 29 filter lets in a little less visible light than the Red 25.

[will_legge]

There is not much exposure latitude with this film. The tricky thing

is the amount of infrared radiation varies with location, time of

day, atmospheric conditions, and time of year. I have had as much as

a two stop difference in the metered exposure between summer and

winter.

 

 

Konica is also unsure of the correct development time. Their data

sheet says 6 minutes in D-76, but the film box says 9 minutes in D-

76. Also the degree of infrared radiation can greatly affect image

contrast and can affect development time.

 

I would go with the red #25 filter over the orange.

[robert_grasing]

Konica says it makes no difference which filter is used, the red or

the orange. It's basically a blue sensitive and a red sensitive

emulsion, and nothing (or almost nothing) in between. To get the

infrared effect, you just need to cut off the blue sensitive part,

and either the red or the orange filter will do that. The exposure

will be the same for either filter.

 

Konica gives the basic exposure as 1/60 at f5.6 but I get better

results at 1/30 at f5.6 and shortening the developing time.

 

As for refocusing, I set it just halfway to the usual infrared

indicator. It does seem to need less lens extension than the Kodak

film.

 

Anyway, try a few test rolls before you leave.

 

This is, BTW, an old emulsion. I've been using it for almost 25 years

and I've seen references to it in Japanese technical books older than

that. Used to be called Sakura Infrared.

[joseph_e._forks]

The Filter I got is a Tiffen R2 Medium Red. It has a filter factor of 8, which is minus 3 stops? Absorbs violet, blue, green & yellow rays for strongest contrast. Useful for infra-red photography (we'll see).

 

Shooting in the middle of the day was the thing that appealed to me about this film, as I'm sure I'll have many opportunities in the harsh mid day sun when I'm usually saying things like "I wish the light was better!". I have 30 (120) rolls of this film, although I probably won't pack all 30, maybe only 15 or 20 rolls. Still I will pick my scenes carefully and bracket liberally.

 

I really won't have time to run any test rolls today, and even if I did I've never done my own processing, and have no dark room setup.

So I have no clue how I'm going to get this film processed yet.

 

This is going to be a learning experience for me so once again I appreciate the feedback on this topic as I know you have gone over it before.

 

Just have to make a note not to run off with all my 120/220 film in the fridge (been there done that).

 

Best regards to all who took the time

Joe Forks

[kyle_cunjak]

Does the Konica 750 IR still come in the 120 format??

If so, where might I be able to order it. I can't seem to find anything about 750 IR AT ALL in the konica/minolta ordering book for film.

[jacob_banholzer]

bhphotovideo.com had some rolls that expired in 02/04. I just got them back and they turned out great. I used a YashicaMat TLR with a hoya r72 filter. I rated the film a ISO 8 with this filter and bracketed 2 over and 2 under. I kept the f stop at f22 to minimize blurring with this film. This was my first time with infrared and I am excited to finish the other rolls.