Spot metering for transparencies

Paul Ozzello · Sep 1, 2021

So I'm getting really good results exposing negative films using the advice given on another thread : 2/3 box speed, metering shadows and placing them on zone II or III (or TV-IRE VALUE 1 on Pentax digital spot meter)

How should I meter for transparency films? Do I use box speed or 2/3 box speed ? I read elsewhere I should meter the highlights instead of the shadows (I prefer dark blacks to blown out highlights) On what "zone" or IRE value should I place the brightest highlight value?

I also plan on using graded neutral density filters if necessary - should I measure my brightest highlights through the filter?

Paul

Lachlan Young · Sep 1, 2021

Box speed, highlights on IRE-10 on the Pentax (really IRE 100), adjust to taste. Or you can use an incident meter (highlights, not shadows) and box speed, again adjust to taste. If you really get bored, you can waste time looking at the IRE scale to see where your deepest detailed shadows will likely end up for a given detailed highlight - and from there, how much ND grad is needed should be obvious...

Paul Ozzello · Sep 1, 2021

Lachlan Young said:
how much ND grad is needed should be obvious...

Lol no it's not. What is the range in stops of the IRE scale? If I place my highlight on IRE 10 (100) where on the scale do my shadows start blocking up - IRE 1 or higher? Let's assume I'm using Velvia 50.

Alan9940 · Sep 1, 2021

Box speed and, yes, meter for the high values and place them +2 or, at most, +2 1/2 over Zone V. As for the ND filter, I'd meter for the high values through the filter. Sorry, I have a Zone dial on my Pentax meter and don't use the any type of scale.

Lachlan Young · Sep 1, 2021

fatso said:
Lol no it's not. What is the range in stops of the IRE scale? If I place my highlight on IRE 10 (100) where on the scale do my shadows start blocking up - IRE 1 or higher? Let's assume I'm using Velvia 50.

The IRE scale is 5 stops (32:1) which, conveniently, is essentially the extent of the meaningful straight-line part of Velvia 50's characteristic curve (yes you can sometimes squeeze out & reconstruct stuff from the DMax, but I don't think that's what you're after here) - thusly, place your highlights on 10 (100) and anything below 1(10) will start to block up. To take an example, let's say the detailed highlight is EV 15, anything below EV 10 will start to block up - add two stops of ND grad, and your highlight key effectively becomes EV 13, but you can then hold detail to EV 8 (and you can always go the other way and add fill lighting to lift shadows). Does that make sense?

Paul Ozzello · Sep 1, 2021

Lachlan Young said:
Does that make sense?

Thanks for the great explanation Lachlan - makes perfect sense.

Alan9940 said:
Box speed and, yes, meter for the high values and place them +2 or, at most, +2 1/2 over Zone V. As for the ND filter, I'd meter for the high values through the filter. Sorry, I have a Zone dial on my Pentax meter and don't use the any type of scale.

The IRE scale is the one engraved on the meter - which might be covered up by your zone sticker. I trimmed mine down so that I can see both. As it turns out IRE 10 is just between zones VII and VIII

I'll be using graduated filters in addition to a center filter so I'll probably have to deal with film reciprocity... But that's a topic for another thread!

Thanks guys!

iakustov · Sep 9, 2021

Meter for the darkest spot you want to be have details for, meter for the lightest spot, take the average. In my Minolta Spotmeter F there are Memo and Average buttons for this. You want to make sure the difference is not more than 5 stops or so.

Bikerider · Sep 9, 2021

Unless the contrast ranges are excessive with deep shadows and bright highlights I would simply meter from a simple a grey card There is no way that slide film will be able to cope with brightness ranges in excess of 6 stops. (Especially Velvia) I find it better to have at least some highlight detail, rather than plain burnt out film. Sacrifice the shadows to keep highlight detail.

Alan9940 · Sep 9, 2021

Bikerider said:
Unless the contrast ranges are excessive with deep shadows and bright highlights I would simply meter from a simple a grey card

I have done this numerous times as an additional check against my normal metering technique and found that...sometimes it's correct and sometimes it's not. IMO, this isn't a totally reliable way to meter for transparency film.

Alan Edward Klein · Sep 9, 2021

Bikerider said:
Unless the contrast ranges are excessive with deep shadows and bright highlights I would simply meter from a simple a grey card There is no way that slide film will be able to cope with brightness ranges in excess of 6 stops. (Especially Velvia) I find it better to have at least some highlight detail, rather than plain burnt out film. Sacrifice the shadows to keep highlight detail.

I meter for box speed with Velvia 50 and might reduce exposure just a tad to prevent washout of the highlights. I agree you have to sacrifice the shadows. I had to do that with this one. You can see the shadow on the right I tried to lighten with Lightroom but just got too much noise. SO I left it darker than I wanted too. You can sacrifice the shadows but not the highlights.
https://www.flickr.com/photos/alanklein2000/50570908936/in/album-72157715763486212/

Bikerider · Sep 10, 2021

Alan Edward Klein said:
I meter for box speed with Velvia 50 and might reduce exposure just a tad to prevent washout of the highlights. I agree you have to sacrifice the shadows. I had to do that with this one. You can see the shadow on the right I tried to lighten with Lightroom but just got too much noise. SO I left it darker than I wanted too. You can sacrifice the shadows but not the highlights.
https://www.flickr.com/photos/alanklein2000/50570908936/in/album-72157715763486212/

Even on my laptop screen I can see detail in the shadows. If you were to use a scanner such as the last Nikon ones they have a facility to scan in RAW which will retail all of the detail in the original slide. With PS I would ignore Lightroom (I never use it anyway). With PS you can then recover an amazing amount of detail without being a victim of RAW. Even with a scanner that does not have RAW as an option, scan as TIFF and use the channel to get raw conversion (In filters) and this nearly as good.

Alan Edward Klein · Sep 10, 2021

Bikerider said:
Even on my laptop screen I can see detail in the shadows. If you were to use a scanner such as the last Nikon ones they have a facility to scan in RAW which will retail all of the detail in the original slide. With PS I would ignore Lightroom (I never use it anyway). With PS you can then recover an amazing amount of detail without being a victim of RAW. Even with a scanner that does not have RAW as an option, scan as TIFF and use the channel to get raw conversion (In filters) and this nearly as good.

I use Lightroom to edit the V850 scans. How do I use channel to get raw conversion (in filters)?

Bikerider · Sep 10, 2021

If you open up Photoshop - not Lightroom, in the filters options on the top row is the facility to use RAW. You have all the tools available if you used RAW with a camera and had to convert. It hasn't been available for long perhaps 6 months or a little more. I just know it is very useful.

I took a screen shop of your image, converted it to Jpeg and used adobe RAW to lighten the shadows with the shadows/highlights tool of the tree on the right hand side. It didn't take much. I didn't try it but you could also try using the Burn/dodge tool which is on the left hand side in PS

Alan Edward Klein · Sep 10, 2021

Bikerider: Thanks for the ideas. I checked and realized I could squeeze out more from the shadows. I guess I did;t try hard enough. It's good to know that more is available with Velvia 50 than we might think.

Spot metering for transparencies

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