Wednesday, April 18, 2012

F770EXR Review – Part 11 – Large versus Medium Image Size

Here I test large and medium JPEGs against each other so you can see what to expect when shooting JPEGs at either size. To recap why you might want to follow my recommended settings, which are P mode, M size, DR400 and the lowest useful ISO (I shoot Auto ISO 3200 and let the camera choose), the combination of M size and DR400 allows the camera to protect the highlights against up to two stops of overexposure. This is nothing to sneeze at.

But there are always people who just cannot tolerate shooting at 8Mp when there is a 16Mp mode. It gives them the feeling that they have much more room to crop (while this is true from a resolution perspective, in fact from a detail perspective the advantage is not so clear) and that the details will be finer and more clear.

I ran this test in the evening by available desktop lighting, so there is a wicked blue cast over everything. Here is why:

The LED strip light that I use for my keyboard is pretty blue in color and it makes this all too blue. But for the purposes of this test, white balance is pretty much irrelevant.

Because of the harshness of these point sources of light, I reduced the exposure and then pulled it up for the crops a bit to make the details stand out better. But the following pair of images are as exposed, JPEG out of camera with no tweaks. Oops … one small lie there – I normalized the brightness and contrast as best I could with a curve on the M size image.

f770exr  100iso  f/13  1/2  M4:3  DR400

f770exr  100iso  f/13  L4:3  DR100

So far they look about identical, right? So if you are shooting mainly for web, there is no question that M size’s advantages outweigh any perceived resolution advantage.

But what about enlargements?

Well, I have two answers:

1) 8Mp makes excellent 8x10 prints and good quality enlargements up to 13x19, the largest that most people can print at home on special large format printers. So the number of people that actually need more than 8Mp is vanishingly small. Note: I said need, not want. For more info, see

2) For those incredibly few who want to print larger than 13x19 from a 1/2” sensor in a vacation compact (have you submitted yourselves for drug testing?), the value of 16Mp over 12Mp depends entirely on the acuity of the 16Mp. And this is the rub with EXR cameras, even the vaunted X10. They just do not measure up to their full potential.

This is pretty easy to test. Just shoot at both sizes, upsize the 8Mp image to 16Mp to match, and then compare crops of highly details areas. And what to we see?

Remember to click on the image to see it full sized. You may have to click again to expand it in your browser (the + cursor in magnifying glass is a solid hint) …

All of which leads up to compare the large (top) image with the upsized medium (bottom) image. Remember that the bottom ones do not have contrast normalization, so they suffer a bit from lack of depth. That is fairly obvious, but does not constitute a difference in details.

In fact, there is a smaller area circled in a fine red line on the top and bottom feather crops where the L version has distorted the edges sufficiently to create false detail. Almost like moiré. This is the common issue with the Fuji JPEG engine and L sized images. Fine, low contrast details are sometimes mistaken for noise and mangled a bit. The M size binning increases the granularity of the smallest low contrast details, thus rendering them with greater acuity. It’s extremely subtle in the F550 and beyond, but it is visible if you know what to look for.

Anyway, suffice it to say that there is no significant advantage in details here. And remember that this is shown at 100ppi, whereas printing this image will generally be done at 300ppi for 8x10 or 184ppi for 13x19. In both cases, even less likely to see a difference.

So once again, there really is not enough difference to shoot the L size on an EXR camera. And there is some risk for JPEG shooters of mangling the low contrast fine details in L size, even at low ISO. So why bother …


Shoot M size at DR400 for most of your shooting. If you want more punch in your images, experiment with film modes or even better (MUCH better), consider processing your images in an editor like Lightroom 4. It’s so cheap now that there is little excuse for not getting the best out of your photography.