There is no magical size/weight advantage

Started Mar 5, 2014 | Discussions thread
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Re: What "exactly" is an equivalent lens as regards to the sensor size?
In reply to nigelht, Mar 9, 2014

nigelht wrote:

nigelht wrote:

olyflyer wrote:

That's exactly it. Not only to you, but to everybody else. Those lenses are not equivalent, only equivalent to the half... or one third if you are generous, ignoring other, sensor and IQ related issues, like same ISO = more noise if the sensor is smaller.

This is false and assumes that the sensel sensitivity is identical across large and small sensors. There are 1" BSI sensors in production consumer cameras. Are there FF BSI sensors in production consumer cameras?

The LENSES are indeed equivalent in terms of exposure or the ISO would be different. The fact that noise changes at the same ISO is true if I stuck the same lens on a 1" Nikon camera vs 1" Sony camera.

LENS equivalence never has anything to noise performance of a sensor since what sensor it is paired with changes over time or between manufacturers.

Otherwise no lens is rarely ever even equivalent with itself whenever it is placed on a different body and that's just silly.

No, it's not silly. Look at it like this: if I have a D610 and a 50/1.8 and a V1 and 18.5/1.8, I can use the same ISO and aperture with both to achieve the same shutter speed, but the FX combination offer 2.7 times shallower DOF and 2.7 times less noise at the same settings. It was shown many a time, that sensors of different sizes, that are on the same tech level (which means the opposite of comparing the V1 with the D200...), the noise difference is indeed equal to the difference in size.

Practical example: D610+50/1.8 @ ISO3200 and f/1.8 will have 2.7 times less noise and shallower DOF than V1+18.5/1.8 at the same settings.

NOW, if you want to achieve the same level of noise and DOF in the same situation with the V1, you would need a 18.5mm f/0.67 lens. That would be an equivalent lens to the 50/1.8 on the D610.

You have to show me evidence that noise and size is a linear relationship for same generation sensors.

OK, the D800 should have had ISO640 and not ISO500, but if it had, the ISO noise would have been pretty much the same in the above images.

You also assume that all FF sensors performs identically as well as all 1" sensors. Except they don't.

Well, they are pretty much the same, using the same lens and the same technology and the same software and so on. It is more difficult to compare different brand, different cameras and different technologies, unless we know a lot about each of them.

Nikon traded IQ for PDAF vs the route Sony took.

I don't know what you mean.

Likewise an entry level dslr sensor is not as good as the flagship dslr sensor.

No, not if you are shooting raw and use the same software to develop.

Finally, at base ISO the noise difference will be far less than at the extremes.

Yes, well... the above image is taken at base ISO of the V1, yet it is as noisy as the D800 ISO640 would be. If both cameras were at base ISO the D800 would have been even better. The assumption that we can't see any difference at base ISO is just as wrong as many other assumptions concerning cameras with larger sensors. Those are assumptions made on the wrong basis and caused by lack of experience.

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