JD750 Loc: SoCal

OMG it was Yaserex who said that.

Yaserex’s posts never quote correctly, I screwed up when adding the quote delimiter.

I’m sorry that it appears you said that when you did not.

I have requested that admin remove my post.

Ysarex Loc: St. Louis

Nowhere in Tony's video does he claim or demonstrate a two stop difference yet alone an "over" two stop difference. So you're just making that up or you missed what he said?

"If you used ISO 100 film in 3 cameras, took photos of the same scene, same light, same settings, (fstop, focal length), would you see 2 stops of difference due to 3 different rolls of film? Of course not." But you could easily see as much as a 1/2 stop difference due to 3 different rolls of film especially if different film types.

Tony never identifies the first camera he used in his test. I don't have an Olympus camera but I do have a Fuji camera. Let's do Tony's test then using my Fuji XT-4 (same sensor as the XT-3 Tony mentions) and a Nikon Z7.

Critical to doing this right is to use the same lens on both cameras. Otherwise you can have a 1/3 to a 1/2 stop exposure difference from the f/stops in two different lenses. And Tony knows that which raises some questions about what he's doing in that video. He should know better.

I used the same physical lens (35mm f/2) at the same f/stop on both cameras. Both cameras in full manual with standard picture controls and I saved camera JPEGs. In the first illustration below you see the Nikon and Fuji JPEGs side by side and the Fuji JPEG is 1/2 stop darker. To verify that I put the NEF into NX Studio and applied a -.5 EC to generate a new JPEG and placed that side by side with the Fuji JPEG in the second illustration.

That 1/2 stop difference (not over two stops) is expected. The camera manufacturers have told us to expect it and it's written into the ISO standard. (The ISO standard was written by the camera manufactures via CIPA). They decided to give themselves two different methods to determine ISO values for their cameras and wrote that into the international standard. The standard requires that they tell us which method they're using and they do -- it's in the EXIF data. Nikon cameras use the REI method to determine ISO values and Fuji cameras use the SOS method. There's about a 1/2 stop difference between them. Exactly what my test below shows.

Going back to Tony's video, he makes no mention that our cameras use one of two different standards that produce about a 1/2 stop difference in ISO values. Not once does he mention REI (Relative Exposure Index) or SOS (Standard Output Sensitivity). He should know better. Especially if he's going to suggest that their just making it all up arbitrarily. The differences between cameras that he shows in that video can be explained by his seemingly using different lenses and comparing an REI camera with an SOS camera. Olympus uses the SOS standard and I'll bet the first camera he used was REI.

The camera makers are pretty consistent with the standard as it's written. Those of us who have different brand cameras might wish that the camera makers hadn't given themselves the option to use one of two different methods to determine ISO values and that there's a minor difference between them. But they're not hiding that fact. They've told us. I have cameras that fall into both camps and I manage to get along with them just fine.

Picture Taker Loc: Michigan Thumb

When you find the auto settings are not what you want on a camera, and if it is consistently unsatisfactory you can adjust the + of - on your camera or replace your camera.

worldcycle Loc: Stateline, Nevada

Wow, it seems as if I have certainly stirred up the hornets nest here.

Ysarex Loc: St. Louis

Nah, you just brought up ISO which is one of the most misunderstood functions of a digital camera. With all the Youtubers out there adding constantly to the misinformation, prospects are poor for getting accurate info.

srt101fan

Cheer up, when us old film guys move on at least the issue of correlation of digital and film ISO values becomes irrelevant!

BebuLamar

I compare my Nikon F5 and my Nikon Df. One is a film camera and the other is digital. The meters on the 2 cameras match. So at least for the meter calibration the ASA, ISO, are the same. Now the meter on my D1x also read the same but... with the same setting the images from the D1x is darker than that of the Df.

selmslie Loc: Fernandina Beach, FL, USA

I have tested five different cameras from, one Fuji and one Sony before and after removing the Bayer array.

All six examples are within a ½ stop difference even though I used different prime lenses on the Sony and Fuji.

Northrup is a fool.

CHG_CANON Loc: the Windy City

When I first returned to film, I spent a lot of time comparing my EOS 5DIII to the EOS 1v, sometimes using the DLSR to determine the long-exposure setting with a 10x ND. They are 100% consistent, with / without the filters.

selmslie Loc: Fernandina Beach, FL, USA

Typo. That should have been “three from Nikon, “.

Picture Taker Loc: Michigan Thumb

A simple question was asked, the difference of ASA vs ISO.

BebuLamar

The OP asked "What I would like to know is how film ASA correlates with digital ISO" that doesn't make sense as film was rated in ISO too and for about 40 years already.

User ID

And was correctly answered immediately. What followed after that was pure uhh, a wasteland of waste product (note how delicately I put that.)

boberic Loc: Quiet Corner, Connecticut. Ex long Islander

As Im recall some films (dont remember which) had an ASA of 32. But most film cameras did not have such prcise settings. My Canon F1 ASA settings were 25, 50, 100 etc. So I shot it as if it had an ASA of 25. ( Panatomic X comes to mind)

srt101fan

I don't want to speak for the OP, but I think you are wrong. The question he asked is:

"What I would like to know is how film ASA correlates with digital ISO."

You seem to have stopped at the topic title and ignored the body text. (Note that the title isn't even a question!)

If you read the whole post, it's clear his concern is not with the meaning and relationship of ISO/ASA/DIN/GOST/etc standards.

He is asking about the correlation between the speed values assigned to film and the ISO values you set in a digital camera.