SFX and filters

sineadw

I got some (cheap-ass) coloured filters (yellow, red, blue, green orange) for the film slr this morning that I was thinking of using with some SFX I impulse bought last week. My first thought is to use the red for some available-light portrait stuff, but I was hoping to do some more traditional IR shooting too. Google is giving me mixed feedback on what I can achieve with the red filter in that regard though. There seems to be a lot of confusion as to whether you really need to shoot with an R72 or similar to achieve the 'white grass' look, or if it might be too dark. Anyone got personal experience on this one?

thefizz

You do need a dark filter such as the R72 with this film for an IR effect. An ordinary #25 red will not do it for you. Ilford make a plastic filter similar to an R72 for this film which works great. Sometimes they sell a pack of three 35mm films with the filter included. Alternatively, find a cheap filter with a cut-off of around 680nm.

Peter

sineadw

Thanks Peter. Been looking at the Ilford filter alright but I think it's a Cokin based one? Would there be much difference in 680nm and 720nm? Thinking of investing in the Hoya. Gunns (bless them) have it in for 42 quid. I'm not usually averse to cheap filters but from what I'm reading it really does make a difference with IR.

DaireQuinlan

Yeah I have that filter that theFizz is talking about, it's a Cokin P filter, not sure what the cutoff is, probably 720 or so as theFizz suggests. It's barely possible to see through it if the day is sunny and you let your eyes adjust a bit. Cool thing is that you can actually see the IR effect through it, trees, grass, etc are all much paler shades or dark red if you know what I mean

I've also shot SFX with a 25a though, and gotten results that, while not -really- IR were certainly different from what I would have gotten from, say, tri-x.

Here's a properly filtered shot:


Here's one just using the 25a:


I had another much better example from the top of killiney hill using the 25A but unfortunately in a stupid mishap it got erased from flickr ...

I have a bunch of rolls of Efke Aura in the fridge aswell waiting for some sunny weather :-)

thefizz

The 720nm filter is a bit high as the film is only senstive to 740nm and actually peaks at 720nm.

Re cheap filetrs: I used the Ilford filter many times and it worked great, even if it is only plastic. Its cut-off is 680nm.

sineadw

Hmmm.. feck it - Maybe I'll get a cheap lower nm one so. I don't have a thread the same size on any of the lenses I use on the digital anyway so It'd only be very occasional use. Daire, that shot of the little one is gorgeous I love the skin tones...

DaireQuinlan

Ah yes, after some delving,
"lford describes its SFX filter as Very Deep Red, comparable to B+W 092, Heliopan RG695, Hoya R72, and Kodak Wratten 89B. "

The Hoya and the 89B both cutoff at 720, the B+W cuts off at 650, and the Heliopan I assume at 695. So I'd say the 680 should be grand.

-edit-

theFizz wrote:

Its cut-off is 680nm.

Ah right.

sineadw wrote:

Daire, that shot of the little one is gorgeous I love the skin tones...

I kinda blew this one out a little, I might have to go back and rescan the neg at some point. You'll probably get similar skin tones with any B&W film with a 25a, but I think the SFX adds a little something to it. There's a little diffuse glow or something to it that I like.

thefizz

For an much stronger IR effect, try the Efke and Rollei films.

sineadw

DaireQuinlan wrote: »

Ah yes, after some delving,
"lford describes its SFX filter as Very Deep Red, comparable to B+W 092, Heliopan RG695, Hoya R72, and Kodak Wratten 89B. "

The Hoya and the 89B both cutoff at 720, the B+W cuts off at 650, and the Heliopan I assume at 695. So I'd say the 680 should be grand.

Yep - that's what was puzzling me amongst other posts. Just got a 680 on ebay for a tenner including delivery. Sure for that I can see how it goes and get the Hoya at a later date if I'm getting nothing

sineadw

thefizz wrote: »

For an much stronger IR effect, try the Efke and Rollei films.

I can feel a new project coming on

Thanks guys

thefizz

The problem is that some manufacturers name their filters by a higher nm number than what the actual cut-off is. For example, the Heliopan 695 has a cut-off of 680nm, as do the Hoya R72 and Ilford SFX filters.

DaireQuinlan

thefizz wrote: »

The problem is that some manufacturers name their filters by a higher nm number than what the actual cut-off is. For example, the Heliopan 695 has a cut-off of 680nm, as do the Hoya R72 and Ilford SFX filters.

Hoya themselves seem to think otherwise:
http://www.hoyaoptics.com/color_filter/ir_transmitting.htm
Click on the actual filter name itself for a more detailed PDF. At 690 its transmitting 0.05%, by 720 it's at ~42%, and so on.

I've no experience with that particular filter myself though so I guess YMMV.

Fenster

You can duplicate the Woods effect in Photoshop/Lightroom (you should have my preset for this now, Sinead), but it is such an extreme B&W conversion that other weird artifacts creep into the picture, especially in the sky. So, you can do it, but it won't be perfect.

Sinead, have you had a go of a colour filter in combination with your R96/my R72 yet?

sineadw

Haven't had a chance to test drive the R96 at all yet Did some stuff with the R72 in Balbriggan but I'm still not happy with the results on the 5D. Gonna give the 350D a go and see if that helps.

melekalikimaka

sineadw wrote: »

Haven't had a chance to test drive the R96 at all yet Did some stuff with the R72 in Balbriggan but I'm still not happy with the results on the 5D. Gonna give the 350D a go and see if that helps.

i think its not a matter of a camera being better than another, just some are more sensitive, so it just means a longer exposure

sineadw

melekalikimaka wrote: »

i think its not a matter of a camera being better than another, just some are more sensitive, so it just means a longer exposure

Yep, but I'm getting very long exposure times even at higher ISO, and that was with the 72. Hoping the 350D will give me more latitude. Also going to play a bit with how I'm getting the custom white balance. I'm just not getting white vegetation at all.. Read one thing this morning saying to get my 'grass' custom WB example shot before I put the filter on rather than after?

trishw78

sineadw wrote: »

Yep, but I'm getting very long exposure times even at higher ISO, and that was with the 72. Hoping the 350D will give me more latitude. Also going to play a bit with how I'm getting the custom white balance. I'm just not getting white vegetation at all.. Read one thing this morning saying to get my 'grass' custom WB example shot before I put the filter on rather than after?

I'm having the same problem with my white Balance on the 40D.
I've been shooting the Custom White Balance from the grass.

@Fenster if have links or if you're doing the IR thing at the "Share the Knowledge" I'd be interested.

sineadw

I've read that <gasp!> the canon's aren't as friendly to IR as the lower model Nikons. That was what put me in mind of the IR capabilities of the SFX in my press - I wanted to do a comparison...

Trish are you doing a straight Auto-Levels-Colour-Swap thing in PS? I've tried different PP and nothing seems to help, which is why I started thinking about exposure and WB again...

trishw78

DarrenG gave me a link to a website I'll try to find it & I actually read a realife trees were harmed for the making of a book.

thefizz

DaireQuinlan wrote: »

Hoya themselves seem to think otherwise:
http://www.hoyaoptics.com/color_filter/ir_transmitting.htm
Click on the actual filter name itself for a more detailed PDF. At 690 its transmitting 0.05%, by 720 it's at ~42%, and so on.

I've no experience with that particular filter myself though so I guess YMMV.

As the SFX film only extends to 740nm and peaks at around 720nm, i.e. passes most light at 720nm, then there would be little point using a filter that cuts off at 720nm. I have used the R72 on SFX film and it works perfect, suggesting to me that it must be cutting off much lower. My Heliopen 715nm filter is also darker than my R72.

trishw78

This one of the links
http://stevencastle.wordpress.com/2008/06/17/tips-for-infrared-shooting-on-a-d-slr/

sineadw

trishw78 wrote: »

This one of the links
http://stevencastle.wordpress.com/2008/06/17/tips-for-infrared-shooting-on-a-d-slr/

Hmmm.. some good tips in there. Thanks! Hadn't thought to check that the reds were clipped in the WB histogram - was just looking at the brightness one. Maybe that's the issue... Will take a few shots tomorrow weather permitting :cool:

Edit; Just checked and red wasn't clipping in my grass shot...

DaireQuinlan

thefizz wrote: »

As the SFX film only extends to 740nm and peaks at around 720nm, i.e. passes most light at 720nm, then there would be little point using a filter that cuts off at 720nm. I have used the R72 on SFX film and it works perfect, suggesting to me that it must be cutting off much lower. My Heliopen 715nm filter is also darker than my R72.

Oh right, gotcha. Yeah the 'cutoff' point isn't actually a sharp yes or no, there's a gradation that happens on either side. I guess judging from the values in the chart that they define the 'cutoff' point as the mean value between zero transmission and 100% transmission or something similar.

Fenster

I'll be at the Share the Knowledge thingy if my dole starts coming in (next week, I hope). I've dropped links and tutorials before, but beyond that I'm totally at a loss for what to say right now because my brain currently isn't working.

I am literally just in the door from shooting some infrared, so maybe after some dinner and a large Red Bull I will sit down and go through my workflow in detail. I'd offer a video cast, but I swear a lot. O.o