Serious doubts on the D7100 at high ISO

Started Mar 25, 2013 | Discussions thread
mosswings
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Re: Some more samples and...
In reply to edo21, Mar 27, 2013

edo21 wrote:

The D7100 is an improvement of previous nikon dx models but does not shine as i expected.
My personal opinion is that nikon is looking for earning as much is possible, in fact at the moment has a completely incomprensible product line in this segment that is:

D3100 + D3200 + D5100 + D5200 + D90 + D7000 + D7100 + D300S all pontentially able to satisfy most of photography needs apart from personal preferences and particular shooting conditions. The problem is that each model (apart from D300S and D90) seems to be a decreased or a mixed features model respect to what they may be able to offer.

If I were a manufacturer I'd want to earn as much as possible :-).  Part of the feature set is "crass" marketing; but not most of it.

In this product line i'm not able to understand how much does it cost for example a stop or two iso of better performance, how much does it cost a better AF module, how much a better sensor cause every model exceeds another in at least one feature.
Other brand are clearly offering innovations that moved the bar of normal iso performance of their camera at iso 800 and more. I think that in the 2013 a clean range of 800 - 1600 iso would be a normal feature of a camera.

Many would contest your claim.  It is true that the u4/3 line of cameras have made significant advances in their bulk noise performance, but this is because they adopted, in 2012, the Sony EXMOR technology sensors that showed up in the 2010 time frame on Nikon, Sony, and Pentax DX products.  A similar leap in bulk noise performance occurred 2 years earlier with the transition from CCD-based sensors (D80, D100) to CMOS sensors (D90, D300).  If anything, what we have seen is an improvement in the overall camera market so that ISO 800 is a common thing.  But that point was reached long ago by the DX leaders.  Canon, on the other hand, is 2 stops behind. Still.

It would distinguish the previous generation (D90 - D300S) from the new generation camera and help customers to be confident in what they are purchasing.

All the samples and the review on the web agree on the fact that the D7100 starts to show increasing noise from 400 iso.

And so do its older siblings.  This is nothing new.  It is also true that the per-pixel noise level increases as resolution increases for a given technology node. Stated in a more positive way, higher resolution sensors offer lower image noise for a given technology node.

More samples

It's of all evidence that the D7100 under very controlled shooting situation has more resolving power better auto white balance and better iso performance but not as i expected from a 5 years newer camera in comparison with the D90 that's a benchmark of dx segment, even if you have more chance in printing.

You are presuming that it's technologically possible to drop camera noise floors 1 stop every two years, and at a price that consumers are willing to pay.  That's hard, and the low-level measurements on the best sensors bear this out.  It is MUCH easier to decrease the lateral dimensions, up to a point.  Camera sensors have benefited by the dramatic shrinks in feature size made possible by advanced silicon processing.  But the speed/performance improvements gained in the CPU field arise from a quirk of device scaling: smaller devices go faster, and faster in CPUs is better.  Even the smallest feature size devices in CPUs have reached a limit; the new technologies have had to go thinner in order to make devices laterally smaller.  That's not a good thing for image sensors, whose thickness directly affects their ability to store charge (well capacity).

We are, right now, approaching another limit in sensor performance; noise levels are within 1 stop of 1e-, one electron per sensel - and quantum efficiencies are above 50%, 65% in the case of the D5200/7100 at higher ISOs.  It's dang hard to get 100%.  The biggest change right now that could be made to dramatically improve sensor performance is to lose the Bayer array.  It absorbs half the incoming light in the filtration process.  This is why Panasonic is working on a dichroic technique that promises to increase sensor sensitivity by 1 stop at an unknown cost in color accuracy.  But it's nowhere near ready for market.  Other research labs are experimenting with quantum dot sensors, but again, they're 5+ years away from a practical sensor.

Put this all together, and really the ONLY direction that current technology allows camera manufacturers to move is in the direction of higher resolution while holding the line as best they can in per-pixel noise level.  They've done a remarkable but not perfect job at doing so, and in the process have given us a lot of options.  Resolution is not a priori a bad thing.

There's only one other direction they can move: bigger.  Pushing FX is not just a move to increase profit margins; most DX shooters won't move to FX because of cost and weight.  It's also an admission that they just can't go any farther with any currently production-worthy sensor technology.

Once that physical fact of sensing is established, the only other thing that manufacturers can do is add features and operability enhancements.  Hence the loading of the D7100 with most of the best AF and other tech that Nikon has to offer.  Also, why all of the 2nd tier camera manufacturers are offering quirky features like auto-pano, best-picture-selection, enhanced video modes, etc..  The sensor is good enough and ain't gonna get radically better.

More, in my opinion the 24 mp sensor in outdoor situation without tripod needs all your best ability and lenses to get distinguishable results from the other nikon dx products, in the right hand all the nikon dx products may give excellent results.

That's been the case since the D90.  In fact, it's one of the reasons why so many folks are falling all over themselves with the OMD EM5.  It performs about as well as a D90 in a much smaller package.  But again, it's because it's using a technology that compensates for the 1-stop penalty of the smaller sensor...the D7000's.

 mosswings's gear list:mosswings's gear list
Olympus XZ-1 Nikon D90 Nikon D7100 Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR Nikon AF-S Nikkor 70-300mm f/4.5-5.6G VR +1 more
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