The ISO argument

[Ysarex]

Whoops. My mistake. Here is a link to the original .orf file.

Dropbox - 2018-04-02-190527-OlympusHomePhotos.ORF

Got it -- I have to run out now for a couple hours and I'll get back to you later today.

Joe

 

[Ysarex]

Whoops. My mistake. Here is a link to the original .orf file.

Dropbox - 2018-04-02-190527-OlympusHomePhotos.ORF

So first, yes -- no reason for the ISO 400 and that hurts.

You're not getting anything from the front flash fill attempt. So what you basically have is a backlit scene in which you're clipping the highlights nearly pointing into the sun and everything else is exposed less -- a lot less.

Here's a histogram of your raw file:

Your camera reaches clipping at a value of 4096. You can see where each graph basically stops at 4000 and just piles up into the clipping wall. If you follow back from there note how each graph has a small gap of nothing. The difference in your photo between the sky and foreground is such that there's literally an empty space between them.

The young man's face should have been bright enough to register somewhere between EV 1 and 2. I placed a circle on the graph marking the location of the tone data in his face. If we discount the sky for a minute as one photo and look at the histogram only considering the foreground data we have a multi stop underexposure at ISO 400.

Now the sky of course is there and you have part of it recorded. Your instinct was correct -- you can't shoot backlight like that without front fill. Assuming a willingness to still clip the sky your fill flash was at least 1.5 stops less than it needed to be; And there's your noise.

The photo can be noise filtered to pretty good effect. I used a product called NeatImage and ran your photo through.

Joe

 

[eja]

Wow, I feel like I've been to school and actually learned something. . Thank you for the insights. I'm also stunned at how well that noise reduction looks on that image. So, I'm encouraged to try this again, working to get a better fill exposure and observe the results. Maybe, I'll be pleasently surprised with how well a little point and shoot can work when it's given the proper chance.

I'll also have to check out rawdigger. That was geat information that you interpreted from it for me. Thanks again.

 

[Derrel]

Recovering an underexposed Nikon D500 image - WildLight Photography

 

[petrochemist]

I started this thread but I did not intend for it to become some long drama! I have been doing photography as a hobby off and on since 1968 and I understand some of differences between film and digital. I just understand that ISO can effect exposure in the digital camera period. Yes I am done with it!

Actually not the exposure but the brightness of the image.
The ideal exposure for an image will depend on the ISO (in film days at least there's a bit more variation possible today). I think it's high time a new term was coined that does include ISO, for the many situations where photographers use 'exposure' including the speed rating.

 

[Ysarex]

I started this thread but I did not intend for it to become some long drama! I have been doing photography as a hobby off and on since 1968 and I understand some of differences between film and digital. I just understand that ISO can effect exposure in the digital camera period. Yes I am done with it!

Actually not the exposure but the brightness of the image.
The ideal exposure for an image will depend on the ISO (in film days at least there's a bit more variation possible today). I think it's high time a new term was coined that does include ISO, for the many situations where photographers use 'exposure' including the speed rating.

I don't have an answer just an observation. Ilford struggled with the same problem long before digital came along so this is a very old problem. In their Manual of Photography which is arguably one of the more revered reference "bibles" out there they define exposure as expected -- measured in lux seconds as the total amount of light per unit area striking the film; a function of illuminance over time. In other words a function of the two camera controls shutter speed and f/stop. They then go on to acknowledge that the common and casual usage of the term includes selecting film speed (ASA/DIN back then) and they devote some paragraphs to addressing what to do about that. Their solution for the sake of the text is to use the term "exposure" when they mean exposure and to use the term "camera exposure" as the alternate term when they mean setting the exposure in conjunction with selecting a film speed.

So it's a not a new problem for us. The confusion will continue and it's getting worse. I encountered this the other day:

Right there you have Nikon saying; "Increasing ISO allows more light to be captured without adjusting aperture or shutter speed." That's Nikon saying that and with a sexy Indian accent. WTF!

Joe