Rollei Infrared (400 ISO) with a Leica M7

[Richard62]

I have been experimenting with Rollei Infrared (400 ISO). Used a IR 720nm filter, developed in Fotospeed FD10 for 12 mins at 20C. Had great results with a Pentax LX, good density and contrast, but grossly under exposed when used with a Leica M7 despite the same development conditions.. Does anyone have any experience of using the film with a Leica M7? Does the light meter react differently to infrared? any advice would be much appreciated. Thanks

 

[kmg1974]

I would check what type of light meter the m7 has, the lx has a silicone diode that is sensitive up to 1000nm
If you know what type of sensor your camera has you could find a reason. Films were both fresh and the same batch?developer still ok?

 

[Richard62]

Thanks for the reply and info. Both films were the same batch (well I bought 5 from same supplier at the same time) and stored in freezer for the same time. Developer may be problem but there is not a lot of difference in the density of the frame numbers on the edge of the film. I knew the Pentax cell was silicon. Have googled to try and find the type of cell in the Leica but no joy yet but maybe that makes the difference. Just tried IR filter on 50mm lens on each camera and pointed at the same bright and dim subjects. Both cameras give similar readings when the Pentax mirror is locked up and camera wound on so that reading is taken off the checked shutter curtain pattern. Think I will try next film in Leica with one exposure on auto and a second using the reading given on the Pentax. Maybe that way I can find the what exposure compensation is needed on the Leica (or change the ISO) to give decent exposed negs. Thanks again.

 

[ME Super]

On a sunny day in the mid-latitudes, here's how I expose IR400s: Meter with no filter (IE at ISO 400) then add 4 stops exposure. The other way to do this is meter at ISO 25 with no filter, then take the shot with the filter at that setting. I do this in manual mode with the Pentax cameras; it also works with my Ricoh TLR and a handheld light meter (my Samsung Galaxy J3 with the Light Meter app), so this technique should also work with your Leica M7. Manual mode all the way, don't use an AE mode. I also usually go manual focus for this and do some sort of zone/hyperfocal focusing (for example, 28mm lens at f/8 and focused at 10 feet gives me everything in focus from 5 feet to infinity).

 

[Andrew O'Neill]

With 4x5 and the R72 filter, I always give 5 stops more exposure. I use a hand held spot metre... I'd try shooting it without the filter (bracketing), to see if exposure is okay... then go from there.

 

[kmg1974]

What is puzzling is that the m7 would have underexposed the film by a few stops. But you also mention now that the meter readings are similar. There is no chance that the iso was dialed in wrongly is there? I would be very surprised if the leica would give so vastly different exposures compared to the lx, are all K images in the negative weak contrast ? Even if the camera would underexpose you should see a decent spread in densities, though compressed...

 

[kmg1974]

The m7 has a silizium photodiode (I'm guessing that is silicone). The sensitivity seems to be around 60%more sensitive to ingrared than visible. I found this by giggling silizium photodiode. The m7 has a 13% selective metering circle. It could be that the white paint is very ir reflective, so the sensor calculates the amount of light to be too high.
I would do a series, +1,+2,+3...

it may ruin one film, but at lest you would know what the correction should be for the in camera meter

 

[Andrew O'Neill]

If that is the case then, he will have to try bracketing test shots to find which EI will work best with that camera, that film, and that filter...

 

[kmg1974]

as the sensor also responds to visible light, it could be that there is a corrective factor in the camera placed by the manufacturer... (hard to see how this would not be present in the pentax, however)...if you know that your sensor is more sensitive to IR light, you (as manufacturer) may want to prevent that from messing up all the other pictures...
I do not think that you need to test that film, that filter and that camera.... you may be able to get a good idea if you do bracketing, as the sensor most likely will respond the same way for IR regardless... so you dial in a corrective factor and you would be set

 

[Andrew O'Neill]

you may be able to get a good idea if you do bracketing,

That's what I meant by testing.

 

[Neil Grant]

...loads of advice here - but metering with this film (as you've found) is rather haphazard. Very few suggest what sort of exposures you should expect when using this film. From this you'd have a good idea if you were in the right 'ball park' or miles off. It's really not too hard with this film - just don't get too bogged down by technicalities and be prepared to bracket until you've got to grips with it. Anyway, with bright sunlight and R72 filter about 1/4 sec @ f/16. Just think of it as a 4 ASA film with the filter. Then bracket one or two stops more. It's really hard to know what filter factor an R 72 would have but you could easily determine it using the film, the filter, a sensitometer and a densitometer. Finally plotting out the CC with and without filter. But it's just not worth bothering. If a film is always used with a filter there's no point in considering a filter factor. It's just part of normal technique. This is of course a different situation from normal pan films that may be used with a variety of 'contrast' filters - where the concept of filter factors is genuinely useful.

 

[Richard62]

Many thanks for all the advice. It seems that the key things that come from these responses is manual exposure and bracketing which I will try and also remember to keep a record of the exposures for a couple of trial films and see how it goes. I will also check exposures with a separate light meter. I have two rolls left of the first batch and just bought another five rolls and opened some fresh developer (FD10) so hopefully no errors due to batch and development.
Thanks again.

 

[Richard62]

Now tried the film in a Mamiya 330s .Starting to get good results. Awaiting delivery of a clip on light meter which will go down to ISO12 to make the metering a bit easier.

 

[Sirius Glass]

Nikon AF cameras have an IR light which is used for film advancement. That IR light will fog IR film. If the Leica M7 has such a sensor then the answer is no.

 

[trendland]

If

I have been experimenting with Rollei Infrared (400 ISO). Used a IR 720nm filter, developed in Fotospeed FD10 for 12 mins at 20C. Had great results with a Pentax LX, good density and contrast, but grossly under exposed when used with a Leica M7 despite the same development conditions.. Does anyone have any experience of using the film with a Leica M7? Does the light meter react differently to infrared? any advice would be much appreciated. Thanks

If I were you I would soon have a LOOK on an extern light meter. Just in case you intend to shot more IR emulsions. Rollei Infrared is (from the remaining IR Films today) perhaps the best one but there are
a couple of others wich could be interesting for you (each with special characteristics).
Most are also from Rollei.
Forget Ilford SFX this one isn't real good but relative expensive in comparison.
The advantage of an extern light Meter is real great - special with the beginning. Yes it seams to be old
fashioned to use an extern Meter. But this isn't real true.
1) you have the chance to learn real much (with serious workflow)
2) this is perhaps the most advantage : If your exposure was wrong it was you (not the M7 metering)
3) to each Film and in each situation it is no bad idea to mark some notes about condition while shooting. Yeah this is indeed "oldschool" but is is real helpfull for later comparison in concern of exposure.
The special use of IR film would need some additional special workflow (from my point) with normal
bw Film it could be "overdriven" in that described way.
4) if you are sure about exposure and effects in IR photography from more experience you may need
this all not any longer. At last your brain and your remind on light situations becomes your meter.
But with an external Meter you are quite sure when switching your camera types.

Have in mind : Your Leica M7 electronic is able to handle much more numerious values in comparison
Albert Einstein was able. That all within a milisecond.
But in regard of creating a nice picture any camera electronic has less interlectual capacity than an ant.
with regards

PS : Leicas most advantage is coming from Leitz lenses. In the second line the mechanical value is extraordinary. From the electronic side Leica was never on the top (special the metering systems)
let us perhaps say Leica was up to date but a bit later.

With the M6 that changed so you should not worry to shot M7 EVERYTHING is fine.

But (just to Infrared) I would not give the exposure AS a job to the camera metering.

with regards