Originally posted by Kunzite I will remind you once again that Joseph James' "equivalence" does not include noise.
It's all in here:
Equivalence
Search for "MYTHS AND COMMON MISUNDERSTANDINGS", the "assuming "equivalence" is based on equal noise" section.
Noise have to be measured and observed.
Yes, I know. Equivalence cannot encompass noise as a parameter, because too much is dependent on read noise (vs. photon shot noise) and sensor efficiency. However, a direct
application of equivalence is assessing what kit to put together to minimize noise while keeping sensor efficiency in mind. Joseph James himself uses it this way, and has explained scenarios in those terms to people in forums.
For example, given sensors of roughly equal efficiency (same gen)
as measured by DxOMark or sensorsgen or some similar entity, what combo has the potential to give you less noise?
50mm f/1.8 FF
35mm f/1.4 aps-c
25mm f/0.95 m43
You can't use equivalence
alone to answer that, (unless you just go with a very theoretical answer based on "sensors of equal efficiency",) However you can
apply equivalence in combination with the
externally-sourced data to come to a pretty accurate conclusion.
In other words, image noise is dependent on A) Total Amount of Light Falling on the sensor and B) the sensor efficiency.
Equivalence helps you determine A.
.
---------- Post added 06-01-14 at 08:08 PM ----------
Originally posted by Rondec I sense some irritation, Jay.
On this ^^ point you would be correct
I do get irritated when people waffle on a question they just don't want to answer. C'mon, it's like:
Q: "Which car has more HP, A or B?"
A: "I wouldn't buy a car based on power alone."
Q: "I know, neither would I, but I'm wondering because I've seen some conflicting into. I understand you know which has more ponies?"
A: "I'm not sure why you care, it's shouldn't be important to you. Have you looked at the interiors?"
Q: "Yes, please, just.... which has more HP?"
A: "I think it's also important to consider gas mileage, don't you?"
Q: "Yes, but that's not what I'm asking at this particular moment. It's a very simple question. Horsepower?"
A: "In my experience, a buyer gets more out of having a good knowledge of the safety records..."
...etc...
For the sake of argument - say someone heard this statement and really, really wanted to know what the actual situation was - how would you respond to it technically? :
"
I don't know what's so great about your 77mm f/1.8 Limited - I have a 75mm f/1.8 for my Olympus m/43, same FL and just as fast, so it gives me the same shutter speed and noise performance on my camera."
.
Last edited by jsherman999; 06-01-2014 at 07:18 PM.