Seeking help on Infrared Flash Photography

[ulrich.von.lich]

Hello,

I admit this thread is born out-of-date because there isn't pratically any IR film left on the market. How sad it is!

But it happens I am lucky enough to own two rolls of Kodak HIE and an IR-modified Vivitar 283 flash.

I have a few questions before going out to shoot at night, weegee style.


1) Filter factor

According to this website:
https://en.wikipedia.org/wiki/Filter_factor

720nm IR filters have a filter factor of 16, requiring the exposure to be compensated by 4 stops. The IR filter installed in my Vivitar 283 is a similar one (740nm). Does it mean I should use the flash normally as if I was shooting an ISO25 film?

Is that correct? Another website suggest a compensation of at least 7 stops when use a 720nm filter (by saying Efke IR820 is an ISO400 film, and it should be rated at ISO1 ou 2 when using with a R72 filter):
http://www.lomography.fr/magazine/29717-efke-ir820-aura-120-400-iso

Also, the wikipedia website suggests a filter factor of 20 for Deep Red (29) filter, even higher than the number 16 for R72 (690nm IR) filter. Why? (IR filters are basically the black filters, the most opaque ones.)

I am puzzled.


2) IR filters

Since my Vivitar 283 has a 740nm IR filter installed, do I still need to put on an IR filter in front of the lens?

I personally think it's useless because the flash will be the only IR light source in the dark. It would make sense to screw on, for example, a 780nm IR filter but not a 740nm or less. Is that correct?


3) Focus shift

All my lenses have IR marks. But I don't know to which wave length they refer. For example, a 780nm filter should cause more focus shift than a 720nm filter. I think it's more of the filter than of the film, but again I am not sure. When dealing with the focus shift, the Hexar AF seems to have adopted the film approach:
http://www.rangefinderforum.com/forums/showthread.php?t=108399

I still think the HIE won't cause any focus shift when it is shot at ISO400 without any filter.


I appreciate any helpful input, although I'm not sure of getting any at all.

 

[ulrich.von.lich]

4) IR films

If I'm not mistaking, the Ilford SPX 200 is only "IR" film left on the market??


5) Useful links related to IR Flash Photography

Anything helpful that still exists...

 

[Dwig]

...

1) Filter factor
...

I am puzzled.

...

Filter factors vary depending to the light source. Most published filter factors assume sunlight or an artificial light that matches the solar spectrum across the whole sensitivity range of the film. Electronic flashes emit far less IR, relative to their visible output, than the sun or other "black body radiators" of similar color temperature. Lower color temperature black body radiators (e.g. tungsten lamps) generally emit a higher amount of IR relative to their visible output. All of this boils down to only using a filter factor that is based on the output of xenon flash tubes. Factors based on other light sources don't apply.

 

[sevo]

4) IR films

If I'm not mistaking, the Ilford SPX 200 is only "IR" film left on the market??


5) Useful links related to IR Flash Photography

Anything helpful that still exists...

There also is Rollei Infrared from Maco. Like SPX200, this is not really infrared, but near-red traffic surveillance film. There are other films with similar spectral characteristics available as bulk in industrial quantities, and they occasionally get respooled into cartridges under phantastic names and promises they don't live up to - at the end of the day, everything currently available is like SPX 200 or even worse. All are much slower and less infrared sensitive than the average D70 generation Nikon DSLR - and much, much less infrared sensitive than any digital camera with a filter modification.

In a nutshell, there is no real IR film around any more. If you want a spectral range that goes significantly into IR at reasonable speed, digital is the way to go - and having a oldish camera modified will often set you off by less than 20 rolls of film.

For flash, you would have to get a flash without IR blocking filter - not that hard when it comes to studio flashes, which generally have user pluggable tubes (and optionally uncoated replacements). But very few computer flashes fit that requirement, and the ones that do are expensive, even when used. The strobist site has some instructions for DIY rebuilding some popular flashes with clear flash tubes - that probably is what you have. Exposure is a gamble - you'll have to do trial and error tests to figure out the efficiency of the modification and filters used on your film, which could prove difficult if you only have two rolls and no source for more film...

 

[BillBingham2]

I would definitely suggest taking the route of having an older digital camera modified and use it to run some tests.

From there you can go back to film.

In the old days (30-20 years back) I would say reach out to Kodak, they used to have a treasure trove of information.

You might also try the approach picking up a small IR security video camera to use as a test system. I know they have LEDs that only put out IR for these uses and that might work.

You might also look at flash bulbs as a source of bright IR. For longer exposures you can actually paint light on a scene with an off camera blub (long arks during the burning of the flashbulb). I think that IR LEDs might give you the came capability for a lower cost long term.

Hope this helps, if I can think of anything more I'll add it to this thread.

Good luck.

B2

 

[ulrich.von.lich]

Thank you everyone!

Is there any place on earth where I can still buy IR flash bulbs?

I had ignored the fact electronic flashes would emit far less IR lights than the sun. Should I rate the HIE at ISO6 or ISO3 then? I have absolutely no idea on how to interpretate "far less".

The Vivitar 283 shoudn't have any IR blocking filter because otherwise Shane Elen of Beyond Invisible shouldn't have proposed any IR modification to it.

http://www.beyondvisible.com/
http://www.ultraviolet-photography.com/

As to digital IR, I have thought to buy an M8 someday. The problem with SLRs such as the D70 is you can't put any IR filter in front of the lens if you don't wish to see the world like a blind person.

I have figured out my second question. For example, if you use a flash with a 740nm filter and at the same time, put a 695nm filter in front of the lens, you should record IR lights emitted by the flash from 740nm on and ambient lights (or near-IR lights) from 695nm and on. Without any lens IR filter, you shall record all ambient lights, IR and non IR.

 

[ulrich.von.lich]

I should probably buy a cheap digital camera with IR modification to find out at which speed I should rate my HIEs.

I have a new question: what doesn't it mean "a camera IR-converted to 690nm"? As far as I understand, every digital sensor is more or less sensitive to IR spectrum. To avoid it, an IR blocking filter is installed in front of the sensor (with exception like the M8) to cut off permanently the IR sensitivity. And the IR conversion is to remove the factory-installed IR blocking filter. However, isn't the IR sensitivity (to 690nm, to 720nm etc.) a character of the sensor? How can one purpose at the same time 690nm and 720nm conversions to the same camera? Unless it means to replace the factory IR blocking filter by another one of 690nm or 720nm?

 

[sevo]

The Vivitar 283 shoudn't have any IR blocking filter because otherwise Shane Elen of Beyond Invisible shouldn't have proposed any IR modification to it.

Well, the modification consists of removing the permanently installed IR/UV blocking filter, and adding user ecxhangeable IR or UV pass filters. So it obviously has a filter, unless it has been modified...

 

[BillBingham2]

Any of the early generation Nikon DSLRs (e.g. D40x) should work well. Some of them allow for earlier glass without further tweaking. I know all of the early Nikon glass had the IR Dot on them and can be very cost effective.

I don't think that you need a specific IR bulb. My gut says that they put out that spectrum naturally. Look into burning magnesium on a science page on the net.

B2 (;->

 

[oftheherd]

As you see from this, http://www.freestylephoto.biz/category/200-Film/Black-and-White-Film/Infrared-Film Freestyle sells Rollei infrared film and they state deeper that 89B can be used. But their Rollei data sheet at http://www.freestylephoto.biz/static/pdf/pages/product_pdfs/rollei/Rollei_Infrared_.pdf shows otherwise and shows a sharp drop off to a max of 820nm spectral sensitivity. With an 89B or deeper, you would get less and less infra red light.

This seller, http://www.ebay.com/itm/HOYA-55MM-I...395?pt=LH_DefaultDomain_0&hash=item2c9d6dee6b, who seems knowledgeable, states an 89B equivalent would block all light below 900nm. That would mean a film like the Rollei with sensitivity only to 820nm, would get little if any light. I say that since I used to read that you needed to test filters since they may not all have been test well, or were within certain tolerances that might allow more light to get through than the filter was actually rated for.

I haven't shot IR film in something like 25 or 30 years. I seem to recall that I shot Kodak HIE rated at 25 ASA to 'see' through black magic marker obscuring printed information below it. IIRC I metered at ASA 25 then put on a Wratten 25 and shot with a filter factor of whatever was recommended, about 1.5 stops iirc for HIE and the 25 red filter, but I could be way off.

Anyway, no matter, you will need to experiment. SPX 200 and Rollie have different spectral characteristics, and I don't even recall about the HIE, but I think it might have been different from either. Then there is the difference in color output from an electronic flash. I didn't know it was different enough to make a difference. I seem to recall using electronic flash before I quit using IR, using an opaque filter over the lens, with no difference in exposure, but again, that was a long time ago and I could be wrong.

No matter, I think you will enjoy trying different things to see what effects you get. You might want to take good notes so you can repeat what you like.

 

[BillBingham2]

Don't be afraid of pulling apart of electronic flashes to put filters inside. I never did this with a 282, but I have several previous generations (e.g. 192/292, 151/252) with but a good screwdriver and big white sheet of paper to work on. I lay the parts out with drawings as to where they go for each step.

B2 (;->

 

[Dwig]

Don't be afraid of pulling apart of electronic flashes ...

You should be afraid. Great caution should be taken.

The voltage across the flash tube's leads is in the 300-500v range even on the smallest flashes. This can give quite a shock. The voltage can be present even when the batteries are removed.

 

[ulrich.von.lich]

Well, the modification consists of removing the permanently installed IR/UV blocking filter, and adding user ecxhangeable IR or UV pass filters. So it obviously has a filter, unless it has been modified...

Shane sold me a 740nm filter for Vivitar and asked me to use it to replace the stock one which is a simple piece of plastic, I believe. I don't think there is any IR/UV blocking filter is in the Vivitar flash, otherwise, Shane would have asked me to do further modifications.

PS: I did the modification without any battery in the flash, as Shane advocated.

 

[sevo]

SPX 200 and Rollie have different spectral characteristics, and I don't even recall about the HIE, but I think it might have been different from either.

HIE was very different - very sensitive, and that throughout all its spectrum up to 950nm. Ilford is not quite as fast as HIE and only reaches to 760nm (i.e. the barely visible range). Rollei is almost as fast as HIE from visual to about 780nm, then deeply dropping off to a nominal end at 830nm (where it is seven stops slower than HIE and near unmanageable due to reciprocity).

 

[kxl]

I have a new question: what doesn't it mean "a camera IR-converted to 690nm"? As far as I understand, every digital sensor is more or less sensitive to IR spectrum. To avoid it, an IR blocking filter is installed in front of the sensor (with exception like the M8) to cut off permanently the IR sensitivity. And the IR conversion is to remove the factory-installed IR blocking filter. However, isn't the IR sensitivity (to 690nm, to 720nm etc.) a character of the sensor? How can one purpose at the same time 690nm and 720nm conversions to the same camera? Unless it means to replace the factory IR blocking filter by another one of 690nm or 720nm?

The hot mirror is removed and replaced with an IR filter that only lets IR light through.

 

[BillBingham2]

You should be afraid. Great caution should be taken.

The voltage across the flash tube's leads is in the 300-500v range even on the smallest flashes. This can give quite a shock. The voltage can be present even when the batteries are removed.

Very true, make sure you discharge the capacitor (firing off the flash) before you start taking it apart. Don't cross wires with screwdrivers and such. Take the batteries out before you start your disassembly.

Use a screwdriver that isolates your hand from the metal part of the tool (plastic handled) also a good idea.

Use your own good judgement as to if you can do it.

B2 (;->

 

[oftheherd]

HIE was very different - very sensitive, and that throughout all its spectrum up to 950nm. Ilford is not quite as fast as HIE and only reaches to 760nm (i.e. the barely visible range). Rollei is almost as fast as HIE from visual to about 780nm, then deeply dropping off to a nominal end at 830nm (where it is seven stops slower than HIE and near unmanageable due to reciprocity).

Thanks for the update. I couldn't recall on the HIE. I have a couple of rolls in a freezer, but without the boxes and data sheets as I recall. I have never used the other two, but may try the Rollei one of these days soon. I do remember trying HIE with electronic flash, probably a Vivitar 283 or a Sunpak 522, and an opaque Kodak gel filter over my Contax 50mm f/1.4. My remembrance is that it came out OK. But as I said above, that was many years ago and my recollection may be off.

 

[ulrich.von.lich]

The hot mirror is removed and replaced with an IR filter that only lets IR light through.

So a camera with 720nm IR conversion has a sensor that only respond to wavelengths above 720nm? That does spare the need to use an IR filter in front of the lens, but what about the other side of the spectrum? 720nm to where? 850nm? 950nm? Nobody says.

 

[ulrich.von.lich]

Also, does anyone know to what wavelength refers the IR marking on Leica lens or in general?

Can somebody confirm that the focus shift is a matter of the filter used, not of the film itself?

To prevent focus shift, the Hexar AF offers two choices: 750nm and 850nm. The old RFF thread below suggests the former is for Konica IR750nm and the latter for Kodak HIE. But I tend to think it depends on the wavelength of the IR filter. If you use the HIE without filter, then no focus shift correction should be applied at all; if you use the same film with a 750nm filter, then first choice; with a 850nm filter, then second choice. Am I correct?

http://www.rangefinderforum.com/forums/showthread.php?t=108399

 

[ulrich.von.lich]

It's such a pity that ghostbusters and superstitious people didn't manage to save the almighty Kodak HIE nor to make Infrared Photography popular.