aps-c vs FX with FX lens for best results?

[gtewks]

Not sure which is the better option here:

I have D600 full frame - 100mm tokina macro 1.0 magnification with 24 megpx.

The other option is to use my D7000 aps-c sensor, with th 100mm tokina macro and no extension tubes. This gives me 1.5 x magnification. with 16 megpx.

The question is:

If I crop the D600 images down to the "same magnification".. I end up with about the same resolution as the d7000.

So is there any drawback or advantage of one setup over the other?

[SergMal]

Not sure which is the better option here:
If I crop the D600 images down to the "same magnification".. I end up with about the same resolution as the d7000.
So is there any drawback or advantage of one setup over the other?

Here is my experience. I have a nikon d800 (~36Mp).
I can choose aps-c shooting mode and it will work as 19Mp (Dx format 1.5 crop) camera.
On the other hand I have a Nikon d7100 and its is an aps-c camera (Dx format 1.5 crop) with 24 Mp on board.
So I am going to say that it is better to shoot on D7100 if you are going to crop the image down to the "same magnification"

[SergMal]

Not sure which is the better option here:

The question is:

If I crop the D600 images down to the "same magnification".. I end up with about the same resolution as the d7000.

So is there any drawback or advantage of one setup over the other?

In your situation D600 will have ~ 12-13 Mp if you will crop image down to the same magnification. And D700 with 16 megpx.

[gtewks]

yes,,, the crop of d600 gives me a bit less resolution,, but I guess I'm wondering if the presumed better quality image produced by the full frame is worth the minimal reduction in resolution?

[rjlittlefield]

Aside from the small difference in pixel counts, I don't know of any reason to think that the cropped full frame would be either better or worse than just using a smaller sensor. The reputation of full frame cameras for producing better quality images mostly comes from having more sensor area in which to accumulate light, thus giving less noise (at the cost of requiring more exposure). Cropping removes that advantage.

But there can be significant differences in image quality due to different generations of sensors. To know about that, by far the best approach is to shoot a test head to head and look at the images.

By the way, the convention here at photomacrography.net is that we usually talk about either field width or actual magnification from subject to sensor, not some sort of non-physical "magnification" that has been scaled based on sensor size. At closest focus we call your lens 1.0X no matter what camera you put it on. On the full frame sensor that's 36 mm field width, or less if you crop. On the APS-C sensor it's 23.6 mm field width, with no cropping. If you add a 1.4X teleconverter behind the lens, then the combo becomes 1.4X, again on either camera. And that brings up another point: if you have a 1.4X teleconverter, then you might consider testing whether it plays nicely with your macro lens on the full frame camera. Going that route can give you the best of both worlds: a smaller field width combined with a larger sensor.

--Rik

[gtewks]

By the way, the convention here at photomacrography.net is that we usually talk about either field width or actual magnification from subject to sensor, not some sort of non-physical "magnification" that has been scaled based on sensor size. At closest focus we call your lens 1.0X no matter what camera you put it on. On the full frame sensor that's 36 mm field width, or less if you crop. On the APS-C sensor it's 23.6 mm field width, with no cropping. If you add a 1.4X teleconverter behind the lens, then the combo becomes 1.4X, again on either camera. And that brings up another point: if you have a 1.4X teleconverter, then you might consider testing whether it plays nicely with your macro lens on the full frame camera. Going that route can give you the best of both worlds: a smaller field width combined with a larger sensor.

--Rik

I don't quite understand what you have said above...

On my FX camera the macro produces a 1:1 ratio so I called that 1x magnification (correct?)....
On my aps-c camera the macro produces a 1.5:1 ratio using the same lens.

I don't own a converter,,,, I did purchase some ext. tubes but they simply refuse to keep the connection (to much slop between tube and lens). Without the connection I cannot control my aperture and in fact the camera refuses to function at all as it thinks the lens is not attached.


So it sounds like the long and short of it is that there's not enough difference either way to really make a significant difference. I'll do that "head to head" just to see....

The whole reason I was asking is that I would like to have a semi-permanent macro setup that I don't have to break down every time leave the home to shoot. So I thought I'd make my D7000 my dedicated macro setup in the home studio,,

[Charles Krebs]

On my FX camera the macro produces a 1:1 ratio so I called that 1x magnification (correct?)....
On my aps-c camera the macro produces a 1.5:1 ratio using the same lens.

No. With the APS-C camera you are still photographing at 1:1, you are only seeing a smaller part of the image produced by the lens being captured by the sensor.

Imagine both cameras being film cameras and you shoot the same subject at a 1:1 setting on the lens. If you superimposed both slides on a lightbox the subject would be exactly the same size on each piece of film (the magnification is the same). The APS sensor takes in a smaller field size but at the same subject magnification.

[gtewks]

Yes that is true,, I understand the "reality" of the magnification,, but the resulting image is still 1.5x and that's what matters when trying comparing my cameras for the question I originally posed. I'm sure I need to be using better terminology ,, ,but for this moment I'm just trying to figure out which camera to use.

[Pau]

... I understand the "reality" of the magnification,, but the resulting image is still 1.5x and that's what matters when trying comparing my cameras ...

No, the actual magnification on sensor has been very clearly explained by both Rik and Charles. The visual magnification is also related to the secondary magnification that you use to see the image at the monitor or print. Of course if you fill your monitor with 1:1 images taken with both cameras the APSC one will be more magnified...just because the primary image is smaller, i.e. more cropped. The 1.5X "focal multiplier factor" in reality must be called "crop factor" like most people here says, both the focal lenght and magification on sensor remain the same.

At the same magnification with FF you have larger field and with APSC more pixels imaging a smaller field.

(but I feel that my post is unnecessary, this has been better explained by the former posters)

[Charles Krebs]

I realize that you understand what we're saying. And I do see how it may seem to steer away from your original question. Didn't mean to sound too pedantic about it!

I think at the magnifications you are talking about in your original question the answer will depend greatly on the shooting "conditions" (subject, lighting, ISO required...), how the final images will be used, and the relative imaging quality of the sensors compared to each other. These are things most of us can't address. If the bulk of your shots can be taken at or below 1:1 (as set on the lens), the subject and lighting allow you to use base ISO, and you only occasionally need to crop into the full frame image then I would go with the larger sensor. If you are constantly finding that you need to crop into the full frame I would be inclined to use the APS-C camera.

I think one reason we try to emphasize actual magnifications produced on the sensor is because many here are working with magnifications well over 1.5:1. There are many more considerations that need to be made when you are working at magnifications like 10:1 or 20:1. Some of them are best addressed if you are talking about the actual magnification on sensor, and consider the sensor size separately.

[marceppy]

gtewks,

Let me ask a question -> are you concerned about resolution in terms of image quality? Rik's point about the generation of the sensor and the affect of cropping on image quality is well taken. I found that testing a Canon 1D Mark III and a Canon 1Ds Mark III with the same lens produced a visual difference in resolution when looking at pixels (resolution and IQ), however, little difference when not cropping to a very small part of the image (just looking at the overall image). So, the camera you may be considering, may depend on how you plan to use both the resulting images and the camera system by and large.


Rik, I also have a question on your experience with teleconverters and image quality. With film, I understood that using a teleconverter vs extension tubes, could reduce the image quality by approx. 10%. Have you found that to be the case with digital imaging?

If you add a 1.4X teleconverter behind the lens, then the combo becomes 1.4X, again on either camera.

[rjlittlefield]

Rik, I also have a question on your experience with teleconverters and image quality. With film, I understood that using a teleconverter vs extension tubes, could reduce the image quality by approx. 10%. Have you found that to be the case with digital imaging?

I realize that you only asked one question, but I really want to give two responses.

First, I'd like to point out once again that the answers to all questions about image quality depend on what you're measuring. In What does a teleconverter do and why might you use one?, I show a case where adding a 1.4X teleconverter increases resolution on subject by 26% (two additional sets of bars on a standard USAF test chart), compared to using the same lens at the same distance without the teleconverter. But because the image has grown in size by 40%, that also means something like a 14% loss of sharpness from pixel to pixel within the image. So in that pair of images, you get answers of either 14% worse or 26% better, depending on whether you look at "image sharpness" or "level of detail captured in the image". If there's a general rule, it's that you get the best image of any particular subject by optically magnifying that subject to fill the sensor.

Second, you've written "teleconverter vs extension tubes", so I presume you're thinking about two different ways of getting the same magnification on sensor. The answer to that question could go either way depending on gory details of the lens designs. I cannot count how many misguided advertisements I've seen that trumpet the advantages of extension tubes because they have "no extra glass to degrade the image". That's true of course, but it also means they have no extra glass to remove the aberrations that will otherwise get added because the tubes drag the lens away from the focus distances it was designed for. I'm pretty sure I have lenses in my accumulated collection that could make the comparison go either way. But I'm resisting the urge to go find them and confirm that. Instead, I'll just point out that by sticking a 1.4X teleconverter behind my Canon 100mm f/2.8L IS USM macro lens, I get something that no set of extension tubes could ever give me: focus from infinity to 1.4X at the turn of a focus ring, with high quality image everywhere along that continuum.

Does that help?

--Rik

[marceppy]

Interesting. Thanks, Rik.

[alligator]

I also use both DX and full frame nikons. I generally prefer the full frame (I use D 800E) when I am using a "normal" lens, but go to the DX format when I am using microscope objectives.

There is no trade off that I can see, and several advantages, in using a full frame camera as long as you are using a lens that gives good full frame coverage. and that includes macro lenses (with or without extension tubes). But many microscope objectives won't cover a full frame sensor, and even if they do the edges are often too soft, so then it is time to use the smaller format (I use a D7000).

[Edward Ruden]

I understand the "reality" of the magnification,, but the resulting image is still 1.5x and that's what matters ...

That's not clear at all. To help clarify other's explanations, the definition of magnification of an camera/lens system is needed. It is the length of the image projected onto the camera's image plane divided by the length of the object being photographed. What you happen to put in the image plane to record it is irrelevant to this.