Shooting My First Roll of Rollei 400 Infrared Film Tomorrow with 720 Filter, Any Pointers?

[Ivo Stunga]

I feel validated - info from Ilford newsletter

 

[Mark J]

That's a good way to drum up sales ! ... but honestly that seems excessive.
I couldn't justify using more than half a roll of 120 on one shot, that's more expensive than the typical two shots I've been doing on 4x5"

 

[GLS]

I find focusing not to be an issue at all and can give a closeup examples in 135

Hmmm. Don't know what to tell you then. I just dug out the affected roll in question and evaluated the frames again under a loupe.

On this roll I used the 50mm FLE Distagon at apertures between f11 and f13, and the 180 Sonnar at apertures between f8 and f13. Every single frame is back-focused to some degree from where I intended.

In contrast, every other instance when I performed IR focus adjustment on any of my Hasselblad or Pentax 6x7 lenses with an R72 I achieved critical focus exactly where I intended. The exception is my Superachromat, which by design requires no compensation even with "real" IR films.

I suppose it's possible on the bad roll in question some freak other factor caused the mis-focus on every frame, just on that roll, but I find that exceedingly unlikely.

Perhaps I'm just evaluating my results more critically than most.

 

[Mark J]

I'm with you on this GLS. I use about 2/3rds of the adjustment to the red mark, since I believe these were calculated for the old Kodak HIE which goes to 850nm.
We discussed the subject at some length on a thread about SFX 200 recently.

 

[GLS]

I use about 2/3rds of the adjustment to the red mark, since I believe these were calculated for the old Kodak HIE which goes to 850nm.

Yep, perfectly reasonable.

 

[Chuck1]

Rollei ir 400 is the same film as rollei rpx400, or rollei retro 400, or superpan 200?

 

[Andrew O'Neill]

Rollei ir 400 is the same film as rollei rpx400, or rollei retro 400, or superpan 200?

Check this out...

 

[Ivo Stunga]

Hmmm. Don't know what to tell you then.

Nothing but YMMV I guess

 

[Ivo Stunga]

I'm with you on this GLS. I use about 2/3rds of the adjustment to the red mark, since I believe these were calculated for the old Kodak HIE which goes to 850nm

And with currently available NIR films we're working with mere 50nm into NIR: up to 750nm instead of 150 (up to 850nm). If going this route, 1/3 would make more sense on paper.

 

[Mark J]

No, not actually, but not obvious. I have the advantage of being able to analyse lenses on a computer. The focus is already drifting in the red ( if isolated ) relative to a general mix of blue/green/red centred on the green.

 

[Ivo Stunga]

And what color abberation that produces? If chromatic aberration doesn't present or even hints itself with red - then it's good and little if any correction needed to reach those additional 50nm, no? Especially when selecting for red or reflected red/NIR light.

Under sunny conditions you can focus quite easily with 715nm filter, a tad harder with 720, but 695 - no problems at all. I focus through the 715nm filter quite often when conditions allow it.

EDIT:
Corrections.

 

[Mark J]

Secondary longitudinal colour. However the focus shift in red is small enough to be of no practical consequence. The red band goes from approx 610 to 650 anyway, so most of it is fine. However by 720 to 750 I find it's worth doing a correction. It's only at a level that you can say zero is not enough, full correction is too much, and about half is the best ( this tested on HR-50 at f/5.6 ) .

 

[Sirius Glass]

I meter at box speed and then open up 5 f/stops for the 720 filter. I get the best results with the Sun behind the camera and I use Rollei IR 400 film.

 

[Mark J]

Not sure if this helps, but here are the transverse ray errors for the centre field bundle of a Leica 50 f/2 at f/4.
The amount of slope ( tilt ) of the coloured curves indicates how far out of focus they are. Horizontal = good.

 

[1957ExaktaVarexIIa]

For those who are interested: I got nice results with Rollei Infrared 400 as a reversal film - beautiful slides.
720 nm filter. Lightmeter (measuring without filter) between ISO 6/9° and ISO 12/12°.

I use to use the procedure of Friedemann Wachsmuth.
Time for first developer: 11 to 12 minutes. If the film should have been overexposed one and a half or two steps, rather 9 to 9 1/2 minutes.

Handle with kid gloves . The emulsion gets very very vulnerable during the process.

 

[MultiFormat Shooter]

Under sunny conditions you can focus quite easily with 715nm filter, a tad harder with 720, but 695 - no problems at all. I focus through the 715nm filter quite often when conditions allow it.

When you use a 695nm filter, such as the B+W 695/092, do you still rate Rollei Infrared at EI 6? Does a 695 filter let-in more light, such that a change in exposure index is necessary? I ask because I have a B+W 695 filter on-order, after trying an Opteka 720, that apparently cuts-off, way past 720 (Rollei Infrared and Ilford SFX 200 were blank, when I used it. fine without it).

 

[Mark J]

Yes to your question. I would guess about ISO 16, but somebody probably has a hands-on number from a similar filter.

 

[MultiFormat Shooter]

Yes to your question. I would guess about ISO 16, but somebody probably has a hands-on number from a similar filter.

Thanks!

 

[Ivo Stunga]

When you use a 695nm filter, such as the B+W 695/092, do you still rate Rollei Infrared at EI 6? Does a 695 filter let-in more light, such that a change in exposure index is necessary? I ask because I have a B+W 695 filter on-order, after trying an Opteka 720, that apparently cuts-off, way past 720 (Rollei Infrared and Ilford SFX 200 were blank, when I used it. fine without it).

Yes - lower nm number makes for clearer and faster filter as it lets more and more visual light in. Wood Effect is reduced with lower nm values, 695 could produce too little of it to one's liking.

I don't rate it at a particular/hard ISO - instead 2-3 stops are added to measurement in sunlight or 3-4 stops in shade, or 5-6 stops indoors - with 715nm filter. That's all the bracketing and exposure guessing I need to do - max two exposures per scene + unfiltered for reference/fun.

With 695 these values will be different. With 720 - different still.

 

[Ivo Stunga]

This gives me NIR exposures that keeps highlights in check and sky dark - preferable in slides.

Although darkness of the blue sky depends on a lot of factors, time of day included - those extra clear and crispy blue days produce strongest effect.

 

[MultiFormat Shooter]

Yes - lower nm number makes for clearer and faster filter as it lets more and more visual light in. Wood Effect is reduced with lower nm values, 695 could produce too little of it to one's liking.

I hope didn't just waste my money on 695 filter (B+W 77mm) . It though I'd try it, expecting the quality to better than a Hoya R72 (one bitten, twice shy, from the Opteka). Oh well, I guess I'll find-out, when it gets here.

 

[MattKing]

I hope didn't just waste my money on 695 filter (B+W 77mm) . It though I'd try it, expecting the quality to better than a Hoya R72 (one bitten, twice shy, from the Opteka). Oh well, I guess I'll find-out, when it gets here.

The role that the filter plays is to stop visible light getting to film that is sensitive to both visible light and infra-red light.
The film's sensitivity to the visible light is greater than to infra-red light.
So the problem with a 695nm filter is that it may let too much visible light past its defenses, which will tend to overwhelm the film's response to the infra-red light.

 

[MultiFormat Shooter]

So the problem with a 695nm filter is that it may let too much visible light past its defenses, which will tend to overwhelm the film's response to the infra-red light.

That's what I'm afraid of. I guess I can always buy a Hoya R72, if I need to.

 

[250swb]

There's an upside to using a 690nm summed up in one word 'subtlety'. IR can become a gimmicky very quickly especially as people all search for the same type of scene in the same type of light. But for days when you aren't in the mood for 'knock 'em over the head' IR or dull days where there's no prospect of sunlight a 690nm can still lift greens and while not being full-on IR it can still add an 'other worldly' quality and expand the mid tone range.

 

[MultiFormat Shooter]

There's an upside to using a 690nm summed up in one word 'subtlety'. IR can become a gimmicky very quickly especially as people all search for the same type of scene in the same type of light. But for days when you aren't in the mood for 'knock 'em over the head' IR or dull days where there's no prospect of sunlight a 690nm can still lift greens and while not being full-on IR it can still add an 'other worldly' quality and expand the mid tone range.

Good point, I didn't think of it, in those terms.