Filters and Metering

[Bill Burk]

How does the red filter behave with Tmax 400?

TMY2 has a sharp cutoff in the red.

Red filters are great with it.

Meters with deep red sensitivity will overestimate exposure if you meter (a light source having significant infrared) through a red filter.

Tungsten light and sunlit granite on a hot day in the mountains have a lot of infrared.

Hutching’s two stop adjustment makes sense to me.

But don’t accumulate corrections that serve the same purpose.

I rate film speed 2/3 stop lower than box speed to avoid underexposure.

So when I use a Pentax Spotmeter V and TMY2 developed in D-76 1:1 the correction for Hutching’s factor (for me) only needs to be 1 1/3 stop more.

 

[DREW WILEY]

TMax 400, along with TMax 100, sees rather far into red; so these have good linear response not only to 25 medium red filters, but also 29 deep red. Not all films do so well with deep red. I've noticed my B&W 29 is actually a little deeper and than my Tiffen 29.

But the best thing that could happen to Bill's, "Add this and that together, then maybe subtract that, then examine the entrails of an owl and the flight path of pelicans" ... would be to ignore all of that. Just go straight to the sum filter factor itself applied to a direct scene meter reading, and don't meter through the filter at all. So much simpler and more reliable!

With most pan films, the filter factor for a typical 25 red filter is 3 stops. LIkewise for a 29 red in the case of TMax films. But for other films, you might need 3-1/2 or 4 stops for a 29, or might more wisely avoid deep red entirely.

Bill, there are all kinds of granite, some of it dark absorbing heat, much of it light, reflecting heat. There are also big differences between deeply weathered and pitted rock and smooth glacially polish granite, which can be almost reflective. I grew up amidst granite and granodiorite, and have taken innumerable shots of it. I wouldn't worry much about IR. But if someone wants to play with the idea, they can simply buy some near-inrfared film (I don't know what is presently available - I once used Konica), along with a 29 deep red filter. More often, it's going to be foliage which is the big surprise.

 

[BrianShaw]

... then examine the entrails of an owl ...

chicken, preferably a rooster

 

[SodaAnt]

Many digital cameras provide that option. You switch to BW mode and then select the color filter. You use the camera as a director's viewfinder. I use my Olympus E-PL1 micro 4/3 digital camera for these things. See the instruction manual section below. What's nice is you can snap the picture and save it for reference as a jpeg while saving the RAW in color at the same time without the BW and filter effect. The digital camera can be used to select the right lens on my LF camera as well as doing preliminary composition. I record the settings verbally in video mode for transcription later at home and use it as a meter as well since it has center, matrix and spot metering options.

I’d rather not carry a digital camera around just to use as a viewfinder. The advantage of the iPhone app is that I always have the phone with me, and it fits in a shirt pocket.

 

[Sirius Glass]

How does the red filter behave with Tmax 400?

Actually very well. The red filters generally do not do much parting, but the will make the sky from darker to almost black.

 

[Alan Edward Klein]

TMax 400, along with TMax 100, sees rather far into red; so these have good linear response not only to 25 medium red filters, but also 29 deep red. Not all films do so well with deep red. I've noticed my B&W 29 is actually a little deeper and than my Tiffen 29.

But the best thing that could happen to Bill's, "Add this and that together, then maybe subtract that, then examine the entrails of an owl and the flight path of pelicans" ... would be to ignore all of that. Just go straight to the sum filter factor itself applied to a direct scene meter reading, and don't meter through the filter at all. So much simpler and more reliable!

With most pan films, the filter factor for a typical 25 red filter is 3 stops. LIkewise for a 29 red in the case of TMax films. But for other films, you might need 3-1/2 or 4 stops for a 29, or might more wisely avoid deep red entirely.

Bill, there are all kinds of granite, some of it dark absorbing heat, much of it light, reflecting heat. There are also big differences between deeply weathered and pitted rock and smooth glacially polish granite, which can be almost reflective. I grew up amidst granite and granodiorite, and have taken innumerable shots of it. I wouldn't worry much about IR. But if someone wants to play with the idea, they can simply buy some near-inrfared film (I don't know what is presently available - I once used Konica), along with a 29 deep red filter. More often, it's going to be foliage which is the big surprise.

That's what I do - use the factors and stops recommended by the manufacturer of the filter. OF course, I have my film developed in a pro shop and don't use the zone system.

 

[Alan Edward Klein]

I’d rather not carry a digital camera around just to use as a viewfinder. The advantage of the iPhone app is that I always have the phone with me, and it fits in a shirt pocket.

One of the problems I have is I can;t see the screen on a phone especially in bright sun. I keep the digital camera and a regular light meter both in my camera bag.

 

[SodaAnt]

One of the problems I have is I can;t see the screen on a phone especially in bright sun. I keep the digital camera and a regular light meter both in my camera bag.

I have no problems seeing the screen on mine, even in the brightest sunlight.

The phone has lots of other uses too. I have a light meter app in case my hand-held meter dies or I lose it. I use it to take notes, using either the keyboard or voice dictation. I use google maps to drop pins to mark the locations I photograph and I use the camera to record the overall location. I use the calculator app to calculate bellows extension factors, etc.

 

[Alan Edward Klein]

I have no problems seeing the screen on mine, even in the brightest sunlight.

The phone has lots of other uses too. I have a light meter app in case my hand-held meter dies or I lose it. I use it to take notes, using either the keyboard or voice dictation. I use google maps to drop pins to mark the locations I photograph and I use the camera to record the overall location. I use the calculator app to calculate bellows extension factors, etc.

Which app do you use? Does it work on Android phones? Does is have histogram and blinkies?

 

[SodaAnt]

Which app do you use? Does it work on Android phones? Does is have histogram and blinkies?

I don’t know if any of these are available on Android phones as I’ve always had iPhones:

Meter apps:
myLightMeter Pro
Pocket Light Meter
Light Meter Ultra
ZoneView

Viewfinder:
Mark II Artist’s Viewfinder

General:
f/ Tools
Massive Dev Chart

 

[Bill Burk]

Nice thing about infrared film with infrared filters in the mountains is the way it cuts haze.

TMY2 has no significant infrared sensitivity. I’ve exposed it for an hour to direct light source from the ATN Viper illuminator and proved with a little attenuation it’s completely safe for fifteen minutes.

Filter factor is the best proven method.

I caution against adding factors in the same direction.

 

[DREW WILEY]

Either speed TMax with a red or deep red filter will cut through haze to an amazing degree. I once backpacked up toward a series or remarkable pinnacles and arrived at a remote little lake at around 9000 ft elevation, just high enough to get above most of the forest fire smoke below. There was a veiling haze over all those pinnacles themselves, but I found it lovely, much like the atmospheric sense of depth in pioneer blue sensitive plate landscape work. I was using a 360mm lens for 4x5 and took an unfiltered shot. Then, for sake of comparison, I took the same shot using a 29 red filter.

Afterwards, I developed and printed both. In the latter example, the red filter version, I looked at the 16X20 enlargement and wondered why there seemed to be a paper blemish right on the very tip of the pinnacle. I put on my reading glasses, and it turned to be perfectly crisp golden eagle perched up there, which I couldn't have possibly seen myself in person due to all the haze at the time.