Alpha 100 versus Alpha 77

[David Kilpatrick]

This comparison will give you an idea how far we have come in five years, 10 megapixels to 24 (top and bottom respectively), 100% small clips from large view:



To view at full size: http://www.pbase.com/davidkilpatrick/image/138619747

The comparison shows - not from exactly the same position, due to inaccessible areas of field and different seasonal conditions - a similar view with the 16-80mm CZ lens on (top) the 10 megapixel Sony Alpha 100 and (bottom) the 24 megapixel Alpha 77. Both files have been resampled to 5120 pixels wide, which is 17.5 megapixels and corresponds to a double page magazine spread in print, or an A2 print (16 x 24 inches cropped, or similar) from a typical inkjet or photo system.

Both are processed using the latest ACR/CS5 workflow, with zero sharpening and zero NR. Both are handheld shots with SSS at a speed likely to be sharp. The Alpha 100 image was shot at f/11 and the Alpha 77 image at f/8; this is more or less in line with diffraction-limit standards. Other apertures including f/11 were tested on the Alpha 77 but it proved very difficult to prevent the camera focusing on a foreground field even with spot focus selected; the spot area appears to be much larger than the A100, and to comprise the central group of cross sensors rather than just a single one. This f/8 result was the only correctly focused shot out of six taken at apertures between f/5.6 and f/11.

[Greg Beetham]

David that's interesting for sure, but I for one would like to see a comparison of the two reducing their original photos to 1000 pixels at the longest side at the highest quality that fits under the limit ie. fairly typical usage for both cameras.
Greg
Ps. Where did that tree come from, did it grow that much in ten years?

[David Kilpatrick]

I think the tree walked over a bit from the left, my viewpoint was different because of aggressive flies and a muddy field!

At 1000 pixels you would not see the slightest difference between an A100 and an A77, if anything the A100 might look better. Where you do notice the difference is if you enlarge the A77 file to 10,000 pixels wide and do the same with the A100.

My feeling is that the example shows that with a good lens, there is not a great deal of benefit even from the jump between 10 and 24 megapixels. 16, 18, 20 or any other figure in between might prove better than 24 as we know, because of better pixel-level performance.

If I have time I will do a simple test between the biggest pixels in the world (Hasselblad with Phase One P20+ - 4000 pixels over 39mm of sensor dimension) versus some of the smallest (A77 with 4000 pixels across 15.3mm of sensor dimension).

David

[Greg Beetham]

Ok David no difference between the two at typical use, (I wanted too see how well the reduction worked for 24MP versus 10MP), is there some way of demonstrating print quality difference at snapshot size for the family album? I guess there would be some people who print large sizes but not as many who print at standard sizes, in any case isn’t it so that the human eye can’t ‘see’ any finer than a print resolution of around 60dpi?
Greg

[David Kilpatrick]

One thing I can tell you Greg is that the Medium and Small JPEG sizes on the A77 absolutely work well. You can shoot 12 megapixel files and get better sharpness and even lower noise, just selecting JPEG X Fine as the format and if you add DRO+ and the right scene mode - well, you can get fantastic JPEG results direct from the camera.

And here's the second part - if you have the smart telephoto converter enabled, this ALWAYS uses the full resolution but cut down image crop. So, you set 12 megapixel (Medium) JPEG for all your regular shooting. When you press the Smart Converter button, instantly the screen images jumps a zoom by 1.4X (it fills the finder, of course). And you still get 12 megapixels. 2X gives you six megapixels. But if you set small JPEG, 6 megapixels which is really enough for most people, the 2X setting keeps that size and the 1.4X size jumps you up to 12!

Small JPEGs are even better without the zoom, four pixels are used to create every final image pixel. That's like pixel binning in Phase One IQ backs - half area, quarter size file.

Trust me on this one, if you really only want prints up to 10 x 8/A4, 6 megapixels will do it easily and you will get amazing noise performance - shoot easily at ISO 3200. And if you use the 2X smart converter, your 70-300mm suddenly becomes a 140-600mm and the file stays the same size (with more noise of course).

David

[Greg Beetham]

Ah, now I’m really starting too like the sound of all that versatility, picture taking functions that are actually useful, it’s probably something that photographers will have too keep in mind now, the shooting size choices, I wonder how easily they can be accessed?
Greg
ps. I assume there is no option for locking the two main exposure variables (f-stop and shutter speed) and let ISO be the [Auto] third variable, it's something we never had available during the film era but could easily be available now in the digital era.

[David Kilpatrick]

There is no T-AV mode as you describe. But the A77 and 65 have program shift!

And they have PERSISTENT program shift. That is, if you use program, and shift one step towards a faster shutter speed, the camera will continue to use programmed exposure shifted one step to a higher shutter speed, until you switch off or turn program shift back the other way.

David

[redsim74]

Thanks for the additional insights, David.

These are the kind of things you don't usually pick up in 'regular' forum posts.

[Bruce Oudekerk]

Actually I think this is a great example of the difference between the two cameras, but it requires an explanation and a bit of experimentation.

I suspect I have a somewhat skewed take on this. I jumped from a 3MP camera, to a 5MP, to a 6MP camera, to a 24MP camera in the last 10 years. It gave me an interesting perspective on how I should go about printing because EVERYTHING up until that last jump was being up-resed to 360ppi to be prepared for any substantive print. What I would do, was to prepare the print at native resolution with conservative sharpening, save and then upres and tweak the file for print. For much of that time I was using an EpsonR800 which is stupid hi-resolution and I found that images benefitted from what would normally be considered slight over sharpening. Bad habits die hard and I still have a hard time toning images down for web. At any rate, at some point in time I jumped to the slightly larger format Epson R1900 and the much larger 24MP a850. The VERY FIRST thing I noted about the a850 was that I was preparing the base files differently. I’m still unclear if this is the camera, different lenses or both. Previously I had been using 0.6 radius for a sharp image accompanied by varying amounts and (very low or 0) thresholds. On a sharp image (of which I get quite a few) the a850 maxes (mins?) at 0.4 radius where the sharpest images ‘take’ the smallest radius. That seems like a small change from 0.6 to 0.4, but in actuality it is remarkably different in critical preparation. Typically the difference between the 6MP KM7D and the a850 would be that I would bump the threshold up 1 (to 1 or 2) and the amount to whatever the image would take. What I learned is that inherent sharpness demands a smaller radius and conversely a softer image demands a larger radius. I had actually known this for many years but had never benefited by going below 0.6. Perhaps what is more germane to this discussion is that you can’t judge a reasonable base file by its unsharpened RAW conversion. As a point of reference, I never sharpen in ACR except in some circumstances to see the effect of noise and then I undo the sharpening before conversion. They all look a tad soft to me before sharpening.

So my point is that, I would have been falling down shocked if the difference between these two images had hit me in the face…But after appropriate sharpening in PS it’s an entirely different matter. Just for argument’s sake, I took the dual 100% image and copied it into PS and applied USM (200 0.4 2) to the image. It doesn’t matter whether you think it is excessive or not for print at 360ppi. I think not but it is of little consequence) and check out the dramatic difference at this point. The 10MP image remains little changed and the other has a profound effect in my estimation. Fiddle with the numbers to your satisfaction but it’s the final print preparation that substantially distinguishes the two from each other. I think your trying to level the playing field to provide for a fair comparison is inherently biased in favor of a softer image. My take anyway.

With that said and the hand waving finished, I have perhaps over stated my point. I freely admit the somewhere between the 10MP and 24MP cameras the difference in print is moot and the differential is only observable when viewing very large un-cropped images. In that very large print they might start to distinguish them selves from each other, dependant on MP and other image quality markers.

Bruce

[David Kilpatrick]

I should add that I am absolutely sure the 24 megapixel camera is better and many of my everyday shots, especially with lenses like the CZ 16-80mm and the 24mm f/2, have amazingly sharp detail. Also, that using a good lens on the 10 megapixel camera is vital. From using the Alpha 77 with 16-50mm and my 16-80mm, compared directly with the NEX-7 and 18-55mm NEX kit lens (I can not show these images, they were prototypes) I know that lens quality matters on 24 megapixels too...

There's a growing feeling that the best way to improve digital photography is to go for better lenses. I guess I always got great results from the A100 anyway, because I acquired the 16-80mm as soon as it was available and I also had a very good 70-210mm beercan. In fact I regret not having the beercan around now as I would have loved to see what that did on the A77.

David

[Greg Beetham]

David do you have any comparison A77 JPEG’s (the A77 JPEG’s seem very good out of camera) with the same lens at the same subject using 24MP and 12MP?
Greg

[David Kilpatrick]

Here are examples at ISO 3200, using the in-camera sRGB JPEG Standard look, Extra Fine, Normal NR, 1000 pixel clip from each image:

A77-ISO3200-incamera-clip.jpg (426.52 KiB) Viewed 7867 times

Normal full size 24 megapixel file - the noise and balance of sharpening is not bad at 3200 by any means.

A77-ISO3200-12mpix-clip..jpg (480.95 KiB) Viewed 7867 times

The Medium, 12 megapixel, size. As you can see this compares well with the A700 for example, and the noise is finer than the 24 megapixel image exactly as you would expect.

A77-ISO3200-6mpix-clip.jpg (532.55 KiB) Viewed 7867 times

Finally, the 6 megapixel result, which would actually suit many users for family and general shots. The noise is very fine and is an extreme contrast to what, for example, a KM 7D or 5D produces at ISO 3200. It's present, but does not look so different from ISO 400 or 800 JPEGs from the original 6 megapixel camera generation.

I've run a whole set of tests, but the files are too many and too large to post here. I'll need to decide how to make them available. One of the full size 3200 images processed from raw, with no NR at all, is over 34MB as a JPEG!

David

[Bruce Oudekerk]

...and I also had a very good 70-210mm beercan. In fact I regret not having the beercan around now as I would have loved to see what that did on the A77.

David

I, too, would be very interested in seeing a comparison of some of the (old and new) known good lenses on various cameras. With increasing sensel density there will be, once again, a lot of discussion regarding this. From a selfish stand point I am especially interested in any differences a lens makes between the 24MP FF and APS-C sensors. No matter how a test is configured there always is some variable that crops up making comparisons difficult, but with enough information trends become obvious.

…and FWIW I will be very interested in your experiences, in general, with your new a77.

Bruce

[Greg Beetham]

I have to admit that 6MP image looks really clean for ISO3200, now I’m wondering how flexible latitude wise 6MP and 12MP is at say ISO400. Pretty good I'd expect.
Greg

Ps. Bruce I agree, I'd like to see some shots with some good old KM glass, I have a few that I like but as yet they are unknown quantities on the A77.

[bossel]

In fact I regret not having the beercan around now as I would have loved to see what that did on the A77.

Send me the A77 and I do you some test shots with the beercan I actually sold most stuff and now am left with the 16-80 and 70-210/4 only, both getting little use since I mostly take the NEX with me. Will probably invest more into E mont from now on.