how to compare camera to mobile phone?

Started 1 month ago | Discussions thread
Tony Beach Forum Pro • Posts: 11,927
Re: Same settings.....
1

PhotoTeach2 wrote:

Tony Beach wrote:

PhotoTeach2 wrote:

The result was less than 1-stop discrepancy, which can easily be within margin-of-error considering it was indeed a phone w/ probably less-accurate ISO calibration, (compared to "real" camera where ISO calibration would be more accurate).

I'm sure you meant ISO "calibration," which is a misnomer as ISO is whatever the camera company says it is and does not reflect a standard of "accuracy."

Well, no ... there is a "standard"

What is the standard? I know it, but do you? It's arbitrary and it even says so.

Then why can I pick up a 50yo (properly working/calibrated) hand-held light meter, use it to arrive at proper "settings" on my brand-new digital, (or even cell-phone).

I can change the final output from a given exposure and thus the ISO by merely changing some image settings. When you grasp that then you have answered your question.

And here you mention "less than 1-stop discrepancy".

The additional doubling of ISO (1200 to 2400) would normally be another stop, (causing that image to be "1" stop lighter/brighter)

So since his (available "M") f/stop was MORE than "2" stops, and he could ONLY GAIN "2" stops w/ his LONGER SHUTTER-SPEEDS (from 1/4-second "to" 1/2s, "to" 1-second), he NEEDED that extra (1-stop from 1200 "to" 2400), ISO (lightness) boost.

He could shoot at about 2.5 stops higher ISO with his camera over the phone and get the same results.

The POINT is that he didn't have to make ANY (exposure/lightness) "setting" changes ... IF ... his "M" lens simply had f/1.7, (as phone did).

You simply don't get it. He could set his camera to f/7 with the same shutter speed, accept the higher ISO, and get the equivalent amount of light (not "lightness") that he can get from his phone at f/1.5.

That is exactly the intended way to "offset" f/stops and shutter-speeds for equal/same exposures, (when you want/need to prioritize either aperture or shutter-speeds).

It is exactly the REASON for "A" and "S/Tv" and "P" auto-modes. They will each provide the exact-SAME "exposure" .... but w/ different (offsetting) A and S/Tv settings.

What you are missing is that he can get the same shot shooting his camera at f/7 and raising the ISO to keep the exposure speed constant.

(1) You keep missing the POINT ... he didn't need to make a (total) 4.5-stop shift as the "equivalence" gurus claim.

Then he ends up with a different composition as DOF is part of the composition (as well as the image quality).

(2) You keep missing the POINT ... he didn't need to make ANY (setting) changes if he simply had f/1.7 available on his (M) lens.

Again, if he wants a different composition.

I consider it bad advice to reduce all the decisions a photographer makes to simplistic rules-of-thumb such as this. That said, this has nothing to do with image quality.

BTW, nothing stops a person from stopping down their larger format lens to match the DOF they get with a smaller format lens that has the same FOV.

To get the same DOF I would have on RX10 @ f/16, I would need f/45 on FF. How many (FF) lenses do you have w/ f/45 ???

Get back to me with the DOF you are trying to achieve with those settings. Also, consider that diffraction is an issue regardless of format.

Take away the noise reduction and start from scratch with those files and see what you have. The smaller sensor is collecting less light overall, and that is reflected by the size of the lens pupils used in the f-number comparison where the pupil of the shorter focal length used on the smaller sensor is actually letting less light through than the smaller f-number but larger pupil on the longer focal length being used on the larger sensor.

But equivalence DOES APPLY to Focal-Length, DOF, and noise-level, (but noise may hot-water if below noticeable or objectionable level).

What I find objectionable about the images shown was the level of noise reduction applied, which wiped out resolution. What I find objectionable about your "teaching" here is that you hint at the relationship between equivalence and image quality and then dismiss it as unimportant. The reason equivalence IS NOT overblown is that it gives us a tool that shows that one can indeed match the output from a smaller sensor to a larger one if you understand that the actual pupil size of the lens being used has to be the same on both formats and that you can't match the results if you only match two of the three variables (FOV, shutter speed, and aperture size) that constitute equivalence.

Thank You again for noticing/pointing-out my (f/2) omission, but this is not helping the OP and I will only respond to SergeyAU again in this thread.

I'll believe that when I see it.

He probably could have used his in-camera metering system to arrive at his image, but I think he has LEARNED something from his "experiments" so it was all to a good purpose.

I am happy to continue to help him w/ further endeavors.

He will end up either having a wrong understanding of what goes into getting a comparable shot using different formats or have to unlearn what you are teaching him.

I'm looking forward to your non-response.

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