Sfx 200 nd r72

[guillermo_saucedo]

Hello

 

I am brand new with Sfx 200 film, i just got my first roll and i don't want to waste it all in the first trial since its very difficult to get it here, so

i have the 120 format film and filter r72 from hoya, also the sekonic meter so how i actually meter the exposure? Should i add any

compensation of what i actually get from the meter and also should i correct the focus ( i have hasselblad 501 cm with 50 mm cfi) to the

iIR focus?

 

The best detail the better thanks

Am very simple approach so as simpler you have it the better

 

Examples are very welcome

[WJT]

<p>Hi Guillermo. If you are starting out with SFX200 you have to keep in mind that it is not a true infrared film but is considered to be more of an extended red type of film. The response falls off very rapidly beyond 740nm, therefore the filter must have a fair amount of transmission below this wavelength. The R72 should work okay. I have shot this film using an 89B filter and also a B+W 091 which are, I believe, similar to the R72, and I have had pretty good results. You can take a look at my Michigan-Upper Peninsula folder where I have a couple of examples posted.<br /> <br /> There is no need to shift your focus point because this is not a true infrared film. Just focus normally.<br /> <br /> The film is rated ISO 200 and setting your meter for that should work okay. I use a Pentax 6x7 and I set its TTL meter for ISO 200. If you use a hand held meter then you will need to make the necessary filter compensations for the reading.<br /> I had good results developing the film in D76 stock strength for 10 minutes at 68 degrees F.</p>

<p>If you really want to experiment with infrared film then you should get a couple of rolls of the Efke Aura 820 film. That film has a response up to 820nm and you can use a #87 filter, which is visibly opaque. Unlike the SFX, you need to rate this film at EI 1.5 to get good results. Regards.</p>

[guillermo_saucedo]

<p>Thanks a lot</p>

[aplumpton]

<p>I think the R72 blocks more visible light than a deep red filter (72 means 50% cut-off at 720nm; Hoya is the only manufacturer where the number has relationship to wavelength cut-off, the R90 meaning 50% cut-off at 900nm) and you might find that it does a better job with the Sfx200 film than the deep red filters that you can see through (like the B+W 091). As Walter mentions, just put the filter on a TTL exposure camera and use the reading as at least a starting point, or place it over your hand-held meter (set to 200ISO) to get a reading. You might want to compare the R72 to a deep red filter under the same conditions, incorporating live foliage in the scene (IR reflects from the plant chlorophyl) to get an idea of the difference if any.</p>

[q.g._de_bakker]

Since SFX records nothing longer than 760 - 780 nm, using a 900 nm filter will result in blank images.<br>A 720 nm cut-off seems a bit long already, leaving not a lot of film speed. But it will give the most noticable effect.<br><br>Meter without filter. When using a 720 nm filter, add 4 stops to whatever the meter said (or set the film speed 4 stops lower, i.e ISO 25). Then still bracket a stop or two.<br><br>It's good to use the IR index when focussing, yes. Focus visually, without filter, and shift the setting over from the regular index mark to the IR index.

[aplumpton]

<p>Q.G., just to avoid confusion, I mentioned the 900nm filter only to show Hoya's sensible filter identification system (compared to Wratten and B+W identifiers) and not a recommendation to use it with Sfx 200. The R72 is probably the best filter to extract whatever IR imaging the film can provide. R90 would have been useful with the long discontinued Kodak High Speed infrared film.</p>

[q.g._de_bakker]

My calculation was off by 1 stop: 4 stops less than ISO 200 is ISO 12.5 and not 25. Sorry!

[arthur_gottschalk]

<p>Q.G., would the Hasselblad R-3 Red (8X) filter work with SFX film? With Efke Aura 820? </p>

[q.g._de_bakker]

That's just a regular red filter (Wratten 25, i believe), Arthur, so it would work, but without a very pronounced IR-like effect.