Crop Factor, Low Light and Aperture with m4/3 lenses?

Started Jun 15, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: Very simple:
1

bobn2 wrote:

Anders W wrote:

bobn2 wrote:

Anders W wrote:

Just another Canon shooter wrote:

Anders W wrote:

Just another Canon shooter wrote:

Anders W wrote:

FF has the same noise for equivalent images only if the sensors are equally efficient. But as a rule they are not. Smaller sensors tend to be more efficient than larger. See here:

http://www.dpreview.com/forums/post/53189207

Not true. QE of newer sensors is about 53%, see sensorgen, from m43 to APS-C to FF.

Sensorgen doesn't have data for many of the sensors in my sample and are based on fitting curves to numbers that results from previous curve fitting.

It does, for the most relevant bodies.

Why should we use partial data if we can use more complete data? And why should we use fitted data points if we can use real data points?

Anders, if you have good data for a full range of cameras, why not publish it so we can all use it?

I don't have a website for things like these and don't intend to start one. Furthermore, my data are collected for the purpose of a set of specific analyses (those presented in the post I linked to) and are sampled and designed specifically to that end. I don't think they are of much interest for any other purpose.

But if you or anyone else want a copy of my Excel spreadsheet for the purpose of replicating or verifying what I have done, I am of course willing to share it. The raw data from which I start out are already available via DxO and, in line with scientific practice, I have already made it clear exactly which data I use and what I do with them. Hence, everyone has had the opportunity to replicate my analysis from the very beginning.

That would be interesting. I've read some of your posts on this, but am still far from understanding how your analysis works, just that it produces results that you like. So, a look at the spreadsheet would be revealing.

I'll see if I can put together a version an intelligible version of the spreadsheet for you. I may not be able to do it right away but I'll see what I can do. In the meantime, what more specifically about my analytic procedures is unclear to you? I would appreciate knowing that also for the purpose of preparing the spreadsheet.

Then the sensorgen data with its acknowledged faults would be redundant.

I don't consider the sensorgen data redundant. I just don't consider them as well suited to answering the questions about sensor efficiency that I asked as those I was in a position to assemble myself.

I think the issue is that you cite your own data as the justification for the comments, but it's not clear how the data is derived.

See above. In what specific way(s) is it not clear how the data are derived? I have described that quite meticulously here:

http://www.dpreview.com/forums/post/53189207

Do you have a problem understanding anything I say there (including the quoted text and the other posts I link to for reference)? If so, specifically what?

If it provides useful information, then I think a wider audience might like to see it.

As it is, your 'real data points' seem to be derived from exactly the same data and your method involves 'interpolation' - so the meaning or the word 'real' here is not maybe what most of us would think of as 'real'.

I have made it perfectly clear in which ways my data differ from those of Sensorgen.

Perhaps, but I for one have found it hard to follow.

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Bob

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