Camera system format wars

I'm confused - "a bit more" what, may I ask?

No wonder I was confused.

thanks! So 4x5 inch film is larger than 120 format and therefore has a wider angle of view, eh?

When I worked at Ruston Gas Turbines Ltd in England, they went metric on the Tornado model and issued drawings to the shop floor ...

... a pity that many of the shop machines only had Imperial scales, ho ho!

Anybody remember the "Gimli Glider" ?

en.wikipedia.org/wiki/Gimli_Glider

It's not quite as straight forward as this appears. 120 film (6x7cm) can be used in different frame sizes when shooting, depending on the camera. Frames might be 6x4.5. 6x6 or 6x9. Especially if using 6x9 I don't know that you can say which film gives "the wider view." It is going to depend on the lens. When I shot both 35mm and 21/4 square the standard 80mm lens on my Mamiya C330 gave me about the same angle of view as a 50mm lens on 35mm. When making prints, a different focal length enlarging lens was advisable for 35mm negatives and 120 film negatives. It was a long time ago and I may not have this totally right.

Thanks for the clarification ... apart from snaps, I was never a film shooter and I don't print ... My interest in photography per se started with a Nikon D50 DSLR. So, today, my info came from AI, shoulda said. Not helped by film terminology in that '4x5 film' doesn't have a number like 120 or 220 or 135 for that matter. Almost as bad as digital, where one never knows how big a so-called "APS-C" sensor is! (my Sigma for example is 20.7x13.8mm ... nowhere near APS-C's 25.1×16.7 mm).

so you agree that cameras have 15 stops of DR then out of camera 🤔

so you think that dual iso doesnt exist 🤔 did you also know that the voltage from the sensor is not the voltage that is recorded 😁

Thanks for that clarification.

David

No. Do not put words in my mouth.

Again, do not put words into other people's mouths

A ridiculous question, apparently designed to obfuscate the issue.

Why? Exposure is empirical and quantifiable. I don't see any problem with ISO exposure index numbers. If someone thinks that they have to match scene middle grey with the intended level of middle grey in a raw file based on its ISO, that's not the fault of ISO exposure indices; that's just a blind spot in their understanding of technology.

Just imagine that the image circle projected by the lens was larger than the sensor. Then a crop factor between 0 and 1 (not negative, by the way) gives you the portion of the image that was too large for your sensor to record.

Except Equivalence says no such thing:

www.josephjamesphotography.com/equivalence/#quick

Equivalence relates the visual properties of photos from different formats based on the focal length and aperture of the lens. Neither the focal length nor the relative aperture of a lens change as a function of sensor (for example, a 50mm f/1.4 lens is a 50mm f/1.4 lens, regardless of the sensor behind the lens). However, the effect of both the focal length and the relative aperture on the visual properties of the photo very much depend on the sensor, and scale in direct proportion to the size of the sensor.

They tried, but the person who decided "ISO" should be carried over from film to digital turned their head at the last second. 😁

Hi,

The idea of a crop factor didn't exist until makers stuck a sub-135 size sensor into a body for which only 135 format lenses were available. Kodak did this with both Canon and Nikon film cameras. Then Nikon did it with their D1.

And, so we who used these things had to do a bit of mental gymnastics with regards to what field of view we would get from the smaller sensor using 135 format lenses. And so we thought of that smaller sensor as if we had snipped off part of the film we used to use. A crop, as it were.

The same thing applies today for those of us using 645 medium format lenses on a digital body which has a smaller sensor area than the film did.

And that's really all it's for. Once you get into a system where the maker has designed matching lenses to go with. Then there is no crop factor.

Stan

Good point GB and yes, not negative, duh.

There was no technical need to continue the concept of film ISO/ASA into the digital world because the sensitivity of digital sensors is fixed (no need to quote Aptina at me) and, unlike film, one can not just change the sensors. So the need must have been to keep previous film camera users content with the knob labels on their digital camera - i.e. for psychological reasons.

One big difference is that each ISO-value film matches the light to a proper density - whereas, for digital, the actual sensor exposure changes with ISO setting. So it is that for ISO 800 the sensor is underexposed by a whopping 3 EV in spite of the review image brightness.

If you want to draw a parallel between film and digital, you could consider digital ISO to be an analog of development time for film.

The fist time I have come across a film analogy that makes sense, and is easy to understand.