D500 General Discussion Thread

donaldejose

This makes sense. "3) if the lens just manages to resolve the FX sensor (as many are designed to). FX will look sharp but then the DX sensor will "half" sharpness of the lense." However, I question the underlying premise that many lenses are just designed to manage to resolve the FX sensor. Film era lenses were not designed to just resolve a 12mp FX sensor. Surely, DX lenses were not designed to resolve a 12mp FX sensor. New DX lenses should be designed to resolve a 24mp FX sensor. I cannot imagine that Nikon makes a 24mp sensor standard on its cheapest body and then produces DX lenses which cannot resolve to that extent. So while the explanation makes sense I doubt it is correct.

Ironheart

@donaldejose It is sad but true, lenses actually do suck. A typical MTF starts at 75% resolution and quickly drops from there as you move away from the center:

MTF for the 50mm f/1.8G

Irwin Puts, a Leica guy, puts it rather well:

"We know from the classical debate about the advantages of medium format and 35mm format that the main issue is the size of the negative. A medium format camera can work with a lens that is optically inferior to a lens designed for 35mm sizes because the enlargement factor of the medium format negative is less when we are considering the same print size. It is a simple case: when we have to capture a certain amount of spatial information on a small area, we need a better lens to differentiate the small details. The classical example is the comparison between 35mm and medium format for a print size of A3: that is 30 by 40cm. A 35mm negative needs an enlargement of 12 times and a medium format negative needs an enlargement of about seven times. The lens for the medium format camera can operate at half the number of frequencies to reproduce the same information content on the print. Where the 35mm lens requires a good MTF value for 40lp/mm, the medium format lens can do with that same value for 20 lp/mm. High resolution in itself is not very informative. A new lens designed for a mobile phone has an MTF of 80% for a spatial resolution of 80 lp/mm. This sounds very impressive and it is! But when we relate these facts to the 35mm size, the factual resolution is 80% for 10 lp/mm and then it is quite normal performance!"

From http://www.imx.nl/photo/technique/technique/page41.html

He goes into much more detail on his site, and talks about digital sensor as well, but the description above is pretty obvious whether talking about film or sensor size. Notice we will be right back to needing to talk about such things as Airy disks, Circle of Confusion, Nyquist Limits, and Diffraction. This is because you can't have a discussion of resolution, without considering the size of the thing you are looking at and from what distance.

Paperman

Why are we surprised at all to see a 24Mp FX sensor give better quality then a 24Mp DX sensor ? After all, isn't that the main advantage of an FX sensor ?

Forgetting microns, let's exaggerate and say a DX pixel is 1mm in diameter. The pixel on an FX sensor that would give the same Mpixels would be 2 mm. Imagining a tiny gray ball of 1 mm and 2 mm and looking at both from a distance say 3 meters, which ball would you see more clearly ?

donaldejose

"A medium format camera can work with a lens that is optically inferior to a lens designed for 35mm sizes because the enlargement factor of the medium format negative is less when we are considering the same print size. It is a simple case: when we have to capture a certain amount of spatial information on a small area, we need a better lens to differentiate the small details. The classical example is the comparison between 35mm and medium format for a print size of A3: that is 30 by 40cm. A 35mm negative needs an enlargement of 12 times and a medium format negative needs an enlargement of about seven times. The lens for the medium format camera can operate at half the number of frequencies to reproduce the same information content on the print." This makes sense to me. But I would refer to it as "the inherent enlargement from sensor size to print size factor" because the limiting factor operating here is the required greater enlargement of that original sensor size capture. In other words, you are just zooming in further to get to the same print size but this "decreased sharpness as you zoom in more" factor should be somewhat offset by the increase in megapixels if the lens can resolve that well.

Paperman

donaldejose said:

"...... In other words, you are just zooming in further to get to the same print size but this "decreased sharpness as you zoom in more" factor should be somewhat offset by the increase in megapixels if the lens can resolve that well.

That also means the only time one will see DX sharpness equal FX sharpness is when lens does not resolve enough to show difference between a sensor ( FX ) twice the capacity of another sensor ( DX ). That will be one crappy lens

snakebunk

A higher pixel density gives a higher resolution because it records more of the image information. But a higher pixel density also can reveal more of the lense imperfections. Like heartyfisher says we all know this. I think we just have different ways to describe it.

Another thing that has been discussed before is that a dx sensor actually uses all of the lense, even if it is an fx lense. I think Ade showed this with nice drawings.

Ironheart

I suppose "crappy" is relative. Lack of resolution and diffraction aren't binary, they slowly creep in. There are some lenses that people say are "crappy", err... "not as sharp" wide-open, but start to get better as you "stop them down" This same "not as sharp"-ness is more visible when magnified by a smaller sensor.

Paperman

snakebunk said:

A higher pixel density gives a higher resolution because it records more of the image information. But a higher pixel density also can reveal more of the lense imperfections.....

Terminology - it is the other way around ... Larger the pixel, smaller the pixel "density" ....

Or maybe you meant to say pixel "count " .

Sports

The good explanations keep coming, so here's one more:
A lens has a certain sharpness from its design, purity, precision, etc. Let's (for simplicity) say it can produce 50 Mp spread (not necessarily evenly) over its image circle.
Now, put an FX sensor behind it. It won't cover the full circle, just some rectangel. Turns out it gets "hit" by 30 Mp. The remaining 20 Mp are wasted - primarily by travelling above or below the sensor. Voila, we have "measured" the lens sharpness on an FX sensor, and it's 30 Mp. (Obviously, the result is always lower than the sensor Mp count.)
Now, put a DX sensor behind the lens instead. It'll cover a smaller area, and more Mp will be wasted. Turns out the sensor gets hit by 16 Mp = our DX measurement result.
I suppose DX is always better than the theoretical 2.25 ratio, as it always gets the best part of the image from the lens (the senter).

Paperman

I don't think that explains it Sports ... Resolution of a lens is not cumulative ( to my knowledge ). Pixel count is, but that is not the unit or measure of resolution ( right ? ) even though some do use the Mp figure to refer to resolution.

donaldejose

I just shot my wife Gina and three of her fifty+ year old friends before a "girls night out" with the D500, 24-85 FX lens set to f4.5, auto ISO, and SB-5000 iTT for balanced fill flash and JPEG, not RAW. I was wondering if I would fail to see details because it is "only half as sharp" as if that lens was on an FX body. Here is an image as well as an excerpt 100%. You can judge for yourself. EXIF data is on Flicker; just click on the image.

BVS

Seems like there's some heavy JPG compression or something going on in this photo. The details in the eyes and hair seem oddly blocky. What JPG setting did you have the camera on?

PB_PM

donaldejose said:

BVS: Maybe the sharpness comparison test should be conducted with the Sigma Art 50 on the D750 and the Sigma Art 35 on the D7200 or D500? Shoot both at f4 and at f5.6 to see if there is any significant difference.

The test should be done with the same lens on both cameras. Anything else is short of a true scientific test. Why? By using a different lens you instantly introduce a uncontrolled variable.

Anyway, why is this even an issue? The D500 and D750 are totally different cameras, sensor size aside. One is a sports camera and the other is a general, jack of all trades type camera. People looking at the D500 shouldn't even compare it to the D750, because, as noted they are different cameras, for different purposes. IMO the only head to head competitor for the D500 is the D5.

donaldejose

JPEG large fine. I also had Active D lighting on Auto if that makes any difference. The file was run through Adobe Elements 13 and then through Portrait Professional. Here is the unprocessed file for your examination.

Paperman

All I can say is nobody looks even close to 50 in that photo, let alone being 50+

donaldejose

Paperman: Look at the unprocessed file, you will see wrinkles (which they want me to remove!). These women all do a type of Super Zumba which really tones the body for a youthful look. Some have also had botox and face peels, etc. to remove facial wrinkles. My wife Gina (in the blue top) is 59 this year. Her boobs are natural: no boob job, but she does find good $100+ bras, not padded but they fit and lift well. The lady on the far left is 49 this year. I am not sure about the exact age of the other two women. The special Super Zumba classes they all go to are quite effective. When Gina was with me at the NRF meeting in St. Augustine the one place she wanted to see and take a selfie there was at the Fountain of Youth. Here she is doing just that. She wanted to send the selfie back to her girlfriends who are all working hard to look younger than they are. Sort of an inside joke for them.

Shot with my Coolpix A.

As an aside let me mention that I think that Coolpix A is a great travel camera because it is very small but has a great lens and a DX sensor: a true pocket camera. The lens is 28mm FX equivalent but is sharp enough that you can crop to 50mm equivalent so you really do have a 28mm, 35mm and 50mm range.

Paperman

Looks like your wife has found the fountain of youth

donaldejose

That is what her friends said to her selfie: "you don't need to drink the water there."

donaldejose

www.youtube.com/watch?v=Y3xNR7VMmSw

donaldejose

www.youtube.com/watch?v=CD0yeZmuNbM

heartyfisher

DaveyJ

Marvelous! Great Short Review!

heartyfisher

Nice Vid showing video auto iso of the D500 !!

autofocus

You know you've done something right when the biggest complaint is it has an ISO that may never be used.

dissent

Well, harumpff. You folks aren't making it any easier to hold off until next year for one of these!!

Perhaps the Kumamoto earthquakes have made the decision easier though.