[Class A]

I'm personally only really interested in advantages (1), (2) and (6).

Too bad that (1) does not exist.

And (6) does not make sense either (considering the current sensor landscape). Most existing smaller sensors provide higher resolution than their larger counterparts.

I didn't comment on the original list because I've gone through too many rounds of dispelling FF myths.

---

Last edited by Class A; 08-04-2013 at 05:13 PM.

[rawr]

Too bad that (1) does not exist.
And (6) does not make sense either

There's still a marginal technical element of truth to the points made at (1) and (6). Probably overcome anyway in real-life by modern sensor tech. And also progress in image processing software.

Having said all that, shooting very low-light I'd still be pretty confident that a D600 or 6D at 3200 or 6400 ISO would provide cleaner output than a K-5II. Just enough to make a visible difference, perhaps.

[Class A]

There's still a marginal technical element of truth to the points made at (1) and (6).

I'm pretty sure the graph you have included shows the performance of all cameras assuming the same f-stop. In other words, there is no compensation for the fact that on an FF camera you have to stop down to get the same DOF, if you want to take an equivalent image.

It is basically this stop difference that you are seeing as an "advantage", but it isn't real, if you are comparing apples with apples. The issue, AFAIC, is that "same exposure" is considered to provide a fair comparison. It does not, in my book, because "exposure" is measured per unit area so if you are increasing the sensor area without lowering the exposure you are gathering a lot more photons. Only a faster lens can do the latter (and will produce more shallow DOF as a side effect).

N.B., I'm always assuming equivalent images, i.e., same FOV, noise, DOF, etc.

I'm sort of OK with DxOMark favouring larger sensors, but one should not mistake the higher ISO scores with actually better low-light performance. Larger sensors have better dynamic range, but they have no "light amplification" effect.

The only reason larger sensors can be better in low light is because some lenses for them exist that have no equivalent in the smaller format.

[Nesster]

I gave up, this is all academic to me now.
Reasons of course are personal, and not any sort of objective performance or quality driven ones; though likely we'll appreciate any benefits thereof.

Reason 1: daughter starting art major in photography. Nikon is a brand the college photo departments understand when it comes to digital. She has had trouble with Pentax in such studio situations, getting the strobe lighting to expose properly, and for the camera to focus more consistently.
Reason 2: theoretically daughter can take a F100 to school and have a film and digital swappable kit.
Reason 3: I like old lenses and want a camera that can use them. I'm happiest in the wide angle to 105mm range which has put a damper on my happiness in APS-C.
Reason 4: As daughter's college is two stops from where I work, we can work out gear swaps as needed. She can still use her K-30 to take advantage of our DA 70 and FA 43.

oh, it's a refurbished D-600. I'd have happily bought the same camera with a Pentax mount and logo on it. Now, sadly, it will likely be quite some while before I'll be looking at a Pentax body again - I have to pay for above college

[rawr]

if you want to take an equivalent image.

These equivalency discussions sometimes seem rather strange to me. It strikes me as perfectly plausible that a new D600 will deliver cleaner output and better IQ at low-light than a new K-5II, simply based on how electrically sensitive/efficient the bigger (and sometimes newer) sensors may be. Ditto for how a 12MP D700 does better at low-light than a 12MP K-x, or indeed how a CMOS K-5 will do better at low-light than a CCD K200D.

It will be hard to make equivalent a D700 and K-x if the underlying sensor tech doesn't support an equivalency argument.

[Class A]

Reason 1: daughter starting art major in photography. Nikon is a brand the college photo departments understand when it comes to digital. She has had trouble with Pentax in such studio situations, getting the strobe lighting to expose properly, and for the camera to focus more consistently.

Your daughter should have no problems whatsoever with exposure.
When you use studio strobes, the camera goes into manual. No change of brand will make a difference.

Assuming your daughter uses a K-30, she shouldn't have focusing issues either. A K-5 with a slow lens could prove to yield inconsistent results, but a K-30 should be absolutely fine (just like a K-5 II(s)).

[Class A]

It strikes me as perfectly plausible that a new D600 will deliver cleaner output and better IQ at low-light than a new K-5II, simply based on how electrically sensitive/efficient the bigger (and sometimes newer) sensors may be.

Well, it seems perfectly plausible to assume that earth's seasons are created by the different distances the earth assumes during its yearly cycle around the sun. But it is still wrong.

You write "the bigger" sensor. Note, however, that size does not play a role in low-light capabilities. It may not be plausible, but that does not make it wrong.

It will be hard to make equivalent a D700 and K-x if the underlying sensor tech doesn't support an equivalency argument.

Of course not.

A discussion about sensor size, will always implicitly assume "everything else being the same", i.e., the same sensor efficiency. Having said that, the K-x, K-5, etc. have excellent sensor performance already. Only pretty much minute advances have been made since then.

Don't let your uneasiness with the "equivalence" concept detract from the fact that larger formats do not (per se) buy you better low light capabilities. Have you looked at the "low noise benefit equals zero" thread I linked to earlier?

[Rondec]

These equivalency discussions sometimes seem rather strange to me. It strikes me as perfectly plausible that a new D600 will deliver cleaner output and better IQ at low-light than a new K-5II, simply based on how electrically sensitive/efficient the bigger (and sometimes newer) sensors may be. Ditto for how a 12MP D700 does better at low-light than a 12MP K-x, or indeed how a CMOS K-5 will do better at low-light than a CCD K200D.

It will be hard to make equivalent a D700 and K-x if the underlying sensor tech doesn't support an equivalency argument.

The equivalency has to do with the final image. A K5II with a 135 mm lens at f2.8 and iso 800 will produce an "equivalent" image to a D600 shot with a 200mm at f4 and iso 1600. The noise will be the same in the two images. The way that the you get the improvement in high iso effect is only if you are shooting a faster lens -- aka you are shooting a 200mm f2.8 on the full frame camera. As Class A says, the issue is that there aren't truly equivalent lenses available for APS-C.

[rawr]

the K-x, K-5, etc. have excellent sensor performance already. Only pretty much minute advances have been made since then.

As someone who has recently been spending probably more than 50% of his shooting time at ISO 5000 and ISO 6400 with those cameras, they can indeed deliver decent IQ at those ISO's (supported by good RAW processors). But when I see output from 1Dx's and D600's shot at the same ISO, and even at equivalent apertures and focal lengths, there is often a not-so-minute visible difference.

The noise will be the same in the two images.

Only assuming the sensors are the same tech generation - eg modern Sony sensors, not banding, high chroma Canon sensors, and sensors with the same SNR response curves too. Some sensors SNR falls off a cliff at ISO 800, others have their SNR only decay slowly past ISO 1600.

[Rondec]

As someone who has recently been spending probably more than 50% of his shooting time at ISO 5000 and ISO 6400 with those cameras, they can indeed deliver decent IQ at those ISO's (supported by good RAW processors). But when I see output from 1Dx's and D600's shot at the same ISO, and even at equivalent apertures and focal lengths, there is often a not-so-minute visible difference.


Only assuming the sensors are the same tech generation - eg modern Sony sensors, not banding, high chroma Canon sensors, and sensors with the same SNR response curves too. Some sensors SNR falls off a cliff at ISO 800, others have their SNR only decay slowly past ISO 1600.

Of course, you are right to a certain extent, but I think that is assumed. The K5 never quite caught the D700 with regard to high iso performance, although it did pass it in dynamic range in low iso situations. An original 5D isn't going to out perform a current generation (Sony) APS-C camera, but in general, assuming the same tech, the differences come from the availability of glass. If Sigma releases a bunch of f1.8 zooms for APS-C, then noise differences will be about the same.

[rawr]

then noise differences will be about the same.

Fingers crossed.

[beholder3]

[deleted]

[monochrome]

oh, it's a refurbished D-600. I'd have happily bought the same camera with a Pentax mount and logo on it. Now, sadly, it will likely be quite some while before I'll be looking at a Pentax body again - I have to pay for above college

I had a very similar experience ten years ago with my elder daughter, except,

1. It was Canon
2. it was more heavily weighted to film
3. I got my KX and K 24 - 105 back
4. I have 2 more children so I "paid for college" until 2012

[Nesster]

Your daughter should have no problems whatsoever with exposure.
When you use studio strobes, the camera goes into manual. No change of brand will make a difference.

Assuming your daughter uses a K-30, she shouldn't have focusing issues either. A K-5 with a slow lens could prove to yield inconsistent results, but a K-30 should be absolutely fine (just like a K-5 II(s)).

Of course she will try things with the K-30; I'm not going to let her keep the 600 full time The issues were with her K-x, which I didn't understand either why that would be, but let's say she had the problem at two different art schools and with knowledgeable teachers. At any rate, the K-x is something I'm using now, but will be selling.

[jsherman999]

These equivalency discussions sometimes seem rather strange to me. It strikes me as perfectly plausible that a new D600 will deliver cleaner output and better IQ at low-light than a new K-5II, simply based on how electrically sensitive/efficient the bigger (and sometimes newer) sensors may be. Ditto for how a 12MP D700 does better at low-light than a 12MP K-x, or indeed how a CMOS K-5 will do better at low-light than a CCD K200D.

It will be hard to make equivalent a D700 and K-x if the underlying sensor tech doesn't support an equivalency argument.

As Class A implies, If you want truly equivalent images (same FOV and DOF and shutter speed,) then there's no advantage in low-light/SNR for larger sensors of the same generation, because to get those equivalent images you need to stop down the FF camera about 1.3 stops to get the same DOF for that FOV. If you're shooting in low-light when you do this, you'll need to boost ISO an equivalent amount to maintain the same shutter speed... thus introducing more noise.

In a practical sense, the larger sensor does give a 'low light' advantage because you're probably rarely interested in forcing the image to have the exact same DOF as the aps-c shot would - you're either willing to accept the more shallow DOF - or in many cases, even welcome it.

In other words, we use equivalence to describe the relationship between formats - this doesn't mean that we're constantly striving for equivalent images. This gives FF a very real practical low-light advantage in real-world shooting, and it's why DxOMark scores it like that.

Also, you have to consider the lenses available to both formats. A 50mm f/1.8 on FF is capable of delivering images that would require about a 33mm f/1.2 lens on aps-c, and one of those doesn't exist (yet). Your f/2.8 zooms on FF are the equivalent of f/1.8 zooms on aps-c. Etc...

Sigma has shaken this up now with that excellent 1.8 zoom, but I hear rumours that they're coming out with an f/2 constant 24-70 for FF, and the line moves again

.