Dynamic Range of film

BrianShaw · Jan 2, 2023

Well then… why are you fretting so much? You know what you are doing!

When I shoot chrome, very seldom anymore, I assume a 5-stop range and compute my exposure accordingly. As others have stated, there are plenty of exceptions to that depending…

Alan Edward Klein · Jan 2, 2023

BrianShaw said:
Well then… why are you fretting so much? You know what you are doing!

I don't want to lower the correct exposure for the rest of shot unless I know that it will in fact clip. Otherwise, I'll leave it at the correct exposure.

BrianShaw · Jan 2, 2023

Alan Edward Klein said:
I don't want to lower the correct exposure for the rest of shot unless I know that it will in fact clip. Otherwise, I'll leave it at the correct exposure.

I understand. But sometimes you just need to place a bet and see where the chips fall.

Alan Edward Klein · Jan 2, 2023

BrianShaw said:
I understand. But sometimes you just need to place a bet and see where the chips fall.

I do that all the time. WIth medium format 120 roll film, I would bracket to cover any errors, and still screwed up. But with 4x5 which I shoot now, with Velvia 50 production ending in 4x5, I need a better way.

BrianShaw · Jan 2, 2023

I’ll tell you the better way but you have to keep it a secret… 4x5 Portra or Ektar color negative.

Alan Edward Klein · Jan 2, 2023

BrianShaw said:
I’ll tell you the better way but you have to keep it a secret… 4x5 Portra or Ektar color negative.

I have trouble scanning negative color film. The colors just never look right. With chromes, they're easy to scan and you know immediately if you got the shot just by holding it up to the light.

DREW WILEY · Jan 2, 2023

Here we go, around in circles again, confusing black and white issues and Zone placement with Velvia of all things; and to further complicate that, presuming that digital cameras thinks the same way film does, which they don't. Oh well. As long as the job gets done. Once in awhile I still buy a roll of chrome film to make sure (hopefully) my own metering skills are still as sharp as they once were. Ektar is a bit fussy with respect to correct metering, but nothing like chrome film, especially Velvia.

Just be glad that you aren't shooting 8x10 color film, at around $35 a shot these days along with processing. Bracketing with that would soon make the price of a Spotmeter look like a realistic bargain.

MattKing · Jan 2, 2023

This seems to be more a question of how the viewing and metering and "blinky" system designed for the use of a digital sensor and image processor built into a particular digital camera can be used or modified to mimic the performance of one or more films.
Alan probably needs a film emulation mode for his camera - something built into the firmware that is matched to that sensor, that image processor, and that film.
I don't think anything like that exists right now.

BrianShaw · Jan 2, 2023

I liken it to trying to use a hammer to drive a screw. Can be done but why not use a screwdriver.

alanrockwood · Jan 2, 2023

I must admit that I haven't read the whole thread, so I may have missed something relevant to what I post below, but anyway, here goes.

My suggestion is that dynamic range could be estimated based on slopes picked off from the characteristic curve. The idea is to look at the slopes in the toe and shoulder regions of the curve compared to the maximum slope of the curve. Dynamic range could be defined as those two points on the curve where the slopes are a certain fraction of the maximum slope. A reasonable guess could be a slope of 1/3 of the maximum slope, or perhaps even 1/4 of the maximum slope.

This is similar in spirit to the old fractional gradient way of determining determining film speed, except that in what I suggested above it is based on maximum slope rather than an average slope. I think that what I am suggesting would be a slightly more conservative estimate compared to using 1/3 of an average slope. In fact, one could adapt the method to use average slope instead of maximum slope, though in practice it is likely to make only a small difference in the dynamic range estimate.

Sirius Glass · Jan 2, 2023

Alan Edward Klein said:
My spot meter is 10 degrees and I don;t want to spend $500 on a new meter when my camera already has matrix, center average and 2-3 degree spot. Histograms and blinkies are a bonus. It's of no help to me when you said in an earlier post that your decades of experience tell you where to set the exposure. I don't have that much time left.

Sell your digital camera and you will have more than enough money to buy a Pentax Digital Spot Meter. Since it has Digital in the name you will still feel comfortable.

BrianShaw said:
Yes, you just as easily could use your digital camera or 10-degree spotmeter to do the same. If you promise to not get offended I think I know the “problem “… you want the blinkers to make a decision. Maybe they can and maybe not. That experiment discussed here or on the other site will help immensely in gaining an appreciation for the capabilities of your blinkirs.

When I have nothing better to do I do scene analysis so I can better see SBR and determine potentially difficult photographic scenes. Maybe I mentioned a phone app before, ZoneView. It’s about $7 and helps me immensely. Here is an example:

View attachment 325605

The blue square represents parts of the image that exceed my arbitrarily set limits of 3stops over or under average. Aren’t these functionally somewhat like your blinkies?

P.S. this isn’t exactly the scene I measured in the previous post where I indicated a 7-stop range. This scene doesn’t have the same level of deep dark.

I use this too.

BrianShaw said:
For anyone who objects to EV, here is the Zone version. LOL

View attachment 325606

Another setting of the same app.

DREW WILEY · Jan 2, 2023

If Lewis and Clark had been given all this excellent advice, they would have wisely given up and turned around before they ever crossed the Ohio River. They had a hard enough time contending with the first grizzly bear they encountered. Nowadays, I could imagine them sitting there asking who has the best cellphone calculator program to tell them which gun to pick, or them fiddling with a ballistics website while their companions were getting torn up by the angry bear.

BrianShaw · Jan 2, 2023

The advice isn’t inhibiting photography nearly as much as the questions. Alan seems to be able to take decent pictures without blinkies and advice.

Alan Edward Klein · Jan 3, 2023

BrianShaw said:
The advice isn’t inhibiting photography nearly as much as the questions. Alan seems to be able to take decent pictures without blinkies and advice.

Thanks but I have to be honest. I don't post the ones I've blown. When I shot medium format 120 roll film, I would get an average reading and cover errors by bracketing a half or one stop. It was cheap and fast enough especially since I shoot landscapes on a tripod. I cannot do that now that I'm shooting large format 4x5.

So, maybe I should have started with this question. How do you chrome shooters set the exposure?

Helge · Jan 3, 2023

Alan Edward Klein said:
Thanks but I have to be honest. I don't post the ones I've blown. When I shot medium format 120 roll film, I would get an average reading and cover errors by bracketing a half or one stop. It was cheap and fast enough especially since I shoot landscapes on a tripod. I cannot do that now that I'm shooting large format 4x5.

So, maybe I should have started with this question. How do you chrome shooters set the exposure?

Got to say (for anyone “slide shy” out there) it’s quite rare that I grossly miss exposure on slide. Even on Velvia 50. And I’m not an expert in metering by any stretch.
I “just” take care thinking about any gotchas and stuff that might fool an averaging meter.

runswithsizzers · Jan 3, 2023

Alan Edward Klein said:
I'm using my digital camera's histogram and blinkies as an exposure meter in addition to the other settings usually provided by a digital light meter and camera (ie. f stop, shutter speed, etc.) . The camera I'm using (Olympus E-PL1 micro 4/3) has a sensor dynamic range of 10.1 stops according to DXO. So I assume that clipping occurs in the digital camera at those points at each end of the 10.1 stop range.

Alan, I don't know how much research you have done, RE: digital cameras, histograms, and overexposure warnings (aka blinkies, aka zebra stripes), but I'd want to know a lot more about what, exactly, the digital camera is programmed to tell you. A full discussion should probably be started elsewhere, by someone who has a lot more knowledge than me, but:
- When a specification is quoted for the "sensor dynamic range" I believe that would apply to the RAW file, right?
- And doesn't the histogram/overexposure warning apply to the JPG, and not the RAW file?
- Since the histogram represents the JPG, which has a color profile applied to it in the camera, choosing a different color profile can make the blinkies appear or disappear without changing the exposure.

Each camera manufacturer may have a slightly different goal in mind when creating the algorithm that triggers the overexposure warning. Are you warned when any one color channel is clipped, or only if all three are clipped? Do some camera manufacturers add a safety factor? How does the algorithm treat specular highlights? I don't know.

Alan Edward Klein said:
So, maybe I should have started with this question. How do you chrome shooters set the exposure?

I think this approach is more likely to lead to predictable exposure results than trying to measure and understand the relationship between clipping in digital cameras and analog exposures.

Alan Edward Klein · Jan 3, 2023

runswithsizzers said:
Alan, I don't know how much research you have done, RE: digital cameras, histograms, and overexposure warnings (aka blinkies, aka zebra stripes), but I'd want to know a lot more about what, exactly, the digital camera is programmed to tell you. A full discussion should probably be started elsewhere, by someone who has a lot more knowledge than me, but:
- When a specification is quoted for the "sensor dynamic range" I believe that would apply to the RAW file, right? YES
- And doesn't the histogram/overexposure warning apply to the JPG, and not the RAW file? YES
- Since the histogram represents the JPG, which has a color profile applied to it in the camera, choosing a different color profile can make the blinkies appear or disappear without changing the exposure. YES. SEE BELOW

Each camera manufacturer may have a slightly different goal in mind when creating the algorithm that triggers the overexposure warning. Are you warned when any one color channel is clipped, or only if all three are clipped? TWO CHANNELS REQUIRED Do some camera manufacturers add a safety factor? YES I READ ONE MANUFACTUER ALLOWS ABOUT 1 STOP MORE WITH RAW OVER THE CLIPPING BLINKIE WITH JPEG. How does the algorithm treat specular highlights? I don't know. sPECULAR HIGHLIGHT WILL BLINK. BUT YOU KNOW THAT BECASUE YOU SEE THE RED BLINKIE HIGHLIGHTING THE SPECULAR LIGHT. YOU WILL SEE THAT IN THE HISTOGRAM. BUT IT DOESN;T INDICATE WHICH PART OF THE IMAGE IS CLIPPING. THAT'S THE PURPOSE OF THE BLINKIE. THE PART OF THE IMAGE THAT IS CLIPPED START TO BLINK IN RED. BLACK CLIPPING BLINKS IN BLUE.

I think this approach is more likely to lead to predictable exposure results than trying to measure and understand the relationship between clipping in digital cameras and analog exposures.

From what I've learned: sensor range refers to RAW. Histograms and blinkies refer to jpeg. Color profiles do change blinkies and histogram ranging. Thanks for reminding me. See next paragraph. Clipping usually shows with blinkies flashing when two color channels clip, not one. The camera shows histograms for each of the three channels plus a histogram luminance when the picture is taken. Prior, there's only one histogram that is available. I'll assume that's luminance only.

So with my digital camera set on Daylight, I get about 2.3-2.5 stops above average before they start showing clipping. If I switch to Cloudy for example, it goes up to about 2.7-3.0. If I change the histogram limits to 10-245, I start clipping about 1/3 less of a stop at about 2.0 -2.3. On the shadow side, adjustment stops at -3 stops and it never shows clipping because there are lots more stops left on the histogram. It seems the camera manufacturer favors clipping highlights which makes sense because digital works similarly to chromes. Also, you can pull data out of shadows in scanning that you cannot recover when brightness clips. So you always worry about highlight clipping just as you worry about shadows with negative film.

I believe the histogram and blinkie numbers I'm getting are very close to chromes. So they could be very helpful. If you were spot metering highlights on chrome film to check you don't "clip" them, how many stops would you need before you got concerned?

Chuck_P · Jan 3, 2023

Alan Edward Klein said:
, maybe I should have started with this question. How do you chrome shooters set the exposure?

Withe same care and consideration used in spot metering the important shadow area(s) with my b&w film. Admittedly, I don't shoot 4x5 chrome, but if I did, I would meter the important high value(s) and make the exposure placement for them. Imo, which is worth nothing, I just don't think it would take you long to figure out any adjustments needed in your metering with how your digital slr spot meter is handling your chrome exposures. Been trying to follow this thread but I don't see why it could not be as simple as that.....but as I said, I don't shoot chrome. FWIW, I've used my own analogue Pentax 1 degree spot meter to meter and place an important textural high value for my own 35mm dslr and was quite pleased with the out come, that was some years ago.

Alan Edward Klein · Jan 3, 2023

Slight correction. Color profile between sRGB and Adobe did not seem to change clipping points. Changing the type of light from Sunny to Cloudy, to Fluorescent, etc. did change it. See my paragraph in my post #92.

Alan Edward Klein · Jan 3, 2023

Chuck_P said:
Withe same care and consideration used in spot metering the important shadow area(s) with my b&w film. Admittedly, I don't shoot 4x5 chrome, but if I did, I would meter the important high value(s) and make the exposure placement for them. Imo, which is worth nothing, I just don't think it would take you long to figure out any adjustments needed in your metering with how your digital slr spot meter is handling your chrome exposures. Been trying to follow this thread but I don't see why it could not be as simple as that.....but as I said, I don't shoot chrome. FWIW, I've used my own analogue Pentax 1 degree spot meter to meter and place an important textural high value for my own 35mm dslr and was quite pleased with the out come, that was some years ago.

I don't have and never used a 1 degree spot meter. My light meter does have a 10 degree which is basically averaging the area it's viewing. Since my digital camera has a 2-3 degree spot, I could feasibly use it. As I asked, how do others use their spot meter with chrome film? How do they verify they're not clipping important parts of the image?

ic-racer · Jan 3, 2023

Alan Edward Klein said:
Thanks but I have to be honest. I don't post the ones I've blown. When I shot medium format 120 roll film, I would get an average reading and cover errors by bracketing a half or one stop. It was cheap and fast enough especially since I shoot landscapes on a tripod. I cannot do that now that I'm shooting large format 4x5.

So, maybe I should have started with this question. How do you chrome shooters set the exposure?

My initial response was based on B&W negatives response to light.

If this thread is about chromes, then the exposure is frequently based on a highlight value. Or at least the speed is based on that for sure according to ISO.

My impression of the 'bracket' function on film cameras is to accomadate chrome shooters. A perfect chrome exposure is difficult to predict.

If Cibachrome were revived and I was to start using chrome film again, I'd try to expose it with a camera that has multi-zone matrix metering. Like Nikon F6 or Rollei Hy6 and use a bracket function.

Chuck_P · Jan 3, 2023

Alan Edward Klein said:
How do they verify they're not clipping important parts of the image?

Spot meter with your dslr , expose, develop, evaluate, adjust metering (high value placements) as needed, accept that it may take a few chromes to hone in on the performance of your dslr spot meter capabilities for your chromes........idk, that's how I would approach it.

Craig · Jan 3, 2023

Alan Edward Klein said:
So, maybe I should have started with this question. How do you chrome shooters set the exposure?

For most "normal" landscape scenes i.e. with the sun behind my back and no major specular reflections like sun off water or chrome, I use the matrix meter in my Nikon and it's bang on almost 100% of the time. I've done the whole dance with spotmeters and zones and all that BS and always ended up exactly where the matrix mater said.

As others have said, for most landscapes with chromes, preserving the sky is important; the shadows fall where they will. With all this talk of dynamic range I think it far more important to consider the quality of information in those extremes, rather than the amount. Perhaps you can extract the last little bit of information out of the sky that is overexposed, but it will still look terrible. Similar, anything deep in the shadows will have muddy colour. Sure, you might be able to extract something if it's important, but it won't look nice. So in that regard, I consider the pleasing and useful range of chromes to be less than 5 stops, perhaps 3.

After a while I can look at a scene and just know what the exposure is without using a meter, but that does take experience. At my latitude I find "Sunny 11" is very close to a daylight correct exposure. I.e a typical landscape more than 2 hours after sunrise and less than 2 hours before sunset with iso 100 film will be about 1/125 F11.

Henning Serger · Jan 3, 2023

DREW WILEY said:
Henning, Fuji papers are marketed a little different here - slightly different selection, or simply different names for the same products.

Drew, just FYI, the Fujifilm top premium paper I was talking about - Maxima - is also available in North America under the exact same name:

Fujicolor Crystal Archive Professional Paper Maxima | Fujifilm [United States]

www.fujifilm.com

It was introduced in 2018 at Photokina in Cologne, a complete new development. An outstanding product, perfect for big prints, exhibitions, archival purposes etc..

But back to topic........

Best regards,
Henning

Sirius Glass · Jan 3, 2023

Chuck_P said:
Spot meter with your dslr , expose, develop, evaluate, adjust metering (high value placements) as needed, accept that it may take a few chromes to hone in on the performance of your dslr spot meter capabilities for your chromes........idk, that's how I would approach it.

Alan, you can use your dslr as a spot meter. You can even put on a zoom telephoto lens and narrow the spot even more. Before I bought my Pentax Digital Spot Meter I used my Nikon F100 with a 28mm to 300mm zoom lens as a spot meter for my Hasselblad. Problem Solved!

Dynamic Range of film

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