I've always been a little jealous of the possibility of stacking Teleconverters which Canon shooters seem to be able to do more easily than Nikon photographers. At the same time I've been puzzling over how to get my mind around having a D300 and a D700. Then yesterday on the pier at Padre Island it hit me...

Read More: Stacking Teleconverters -- Nikon Style

David,

I think there's a flaw in your logic, because the actual picture is unlikely of better quality than a similar sized cropped section of the D700.

Both cameras have about the same number of pixels, but the D300 has a smaller sensor. The diagonal of the DX sensor is 1/1.5 of the FX sensor's. Therefore, to obtain a picture of the same size as the D700, you have to blow up the D300-picture by a factor of 1.5.

If you took a crop of the D700 picture corresponding to the size of the D300 sensor, you would have captured the blue heron with less pixels. however, the D300 pixels require blowing up by a factor of 1.5, thus they get being smeared over a larger area - I think in the end the picture quality is practically the same.

The only difference should be that by using the D300, you have a larger picture of the photographed object in the viewer and you can see better what is going on. But even this might not actually be true, since the magnification factor of the D300 viewer is to my knowledge smaller than the one for the D700.

So, unless somebody tells me my reasoning is completely wrong and I am telling nonsense here, would you have two pictures, one from the D300 one from the D700 that you could increase to the same physical size, i.e., identical width & height and compare the quality difference? For the comparison, the cropped D700 picture should cover the same sensor area as the D300 picture.

Achim--You make some good points but I stand by my post & my reasoning. Fundamentally the same arguments you make about D300 & D700 are ones that people have about cropping vs. Teleconverter. Whichever side you come down on you can come down on that side if you replace D700 & D300 with "FX" and "FX with Teleconverter."

e.g. if your logic that the middle 6MP of the D700 is as good or better than the 12MP of the D300 that cover the same image size then you can likewise argue that the middle 6MP of the D700 with no Teleconverter is better than the D700 with a "1.5" TC (of course our current TC options are 1.4 & 1.7, but the point still holds). Either solution to more focal length equivalence is a compromise--cropping or extra lens elements and couplings.

So your analysis may indicate that the D700 with cropping is a better option than using a D300 (although I'm not convinced it is unless you really need the High ISO performance) but by the same token it would probably lead you to conclude you'd rather crop the D700 image than add a Teleconverter in the field.

FWIW, I've certainly not hauled out Imatest to do an image analysis, but from a practical point of view for a given lens the D300 provides a very similar image to a D700 + TC.--David

Hi Dave,

You are right, I was wrong.

This time instead of just blabbing along, I did the calculations. The positive effect the use of the D300 provides in picture resolution is actually quite strong.

Considering just the sensor area used in both cameras for the quality of the picture and ignoring all other effects:
If you take a crop of the D700 sensor that is the same size as the D300 sensor and blow both photos up to a picture of the same size, the resolution of the D300 picture should still be 52.5% better than that from the D700 crop.

And I assume that fact that the D300 only uses the central part of the lens area improves the picture probably even more.

Here are a couple of images taken with a D300 and a D700 with a 500mm lens, same distance full frame. These were at ISO 1600 and were for comparison of noise in the dark background. They do show the size of the capture of both cameras for comparison. Hope these are not too large to post. hcarl

Howdy hcarl,

Thank you for posting those two images. In seven years of shooting with a full frame camera (Kodak 14nx) in the studio and simultaneously using the 1.5x crop series cameras for all my other work I never visualized what was really happening with my distance to subject and lens choice. Your posted images finally cleared up my foggy mind's view on the 1.5x crop factor and what was happening there.

I can't believe that I went that long without a real understanding of what was going on with the DX factor.

Thanks again.

Hi Rick: Glad the 2 images helped in understanding what the difference is. A friend bought a D700 so I was finally able to take some comparison shots for myself. They certainly cleared up any questions I had. The D700 is also at least 1-2 stops better in the high ISO shots and if you have a look in the dark background area you can see the comparison of the 2 at 1600 ISO. The D300 is not bad but the D700 has less noise. hcarl

hcarl,

You made me laugh as it is hard for me to see any noise at all in either of the images. ISO of 1600 and I am still in shock. I quess that is what I get for not having upgraded my working camera bodies since November 2003. I am so used to noise that I don't know what a noise free image looks like.

There is a big surprise in store for me when I decide that a D3 would pay for itself with my work and client base. What I am really looking forward to is breaking out my 400 2.8 again and mating it on a full frame D3. Maybe next year I can rationalize the additional expense on such a heavily depreciated object as a new digital camera body. As it is I am better spending money on marketing than on camera bodies.

Thanks once again for your participation and the posting of those example images.