Photo Jottings

Will cheap APS-C only lenses handle 24mp resolution?

Some people are asking if the fictitious A700 replacement camera, (announced well over a year ago, and now known as the A77) which uses a new 24mp APS-C sensor, will be too much for the older APS-C only lenses, which were designed for 6mp, 10mp, and 12mp sensors, depending on how far back you want to go.

The answer, based on some simple tests with the 24mp Sony A900 is yes, most lenses should be able to show more resolution. Obviously, all the lens’ optical faults will be more noticeable, but that’s just the way it is.  I find the newer APS-C lenses seem better than the rebadged Sony full frame lenses, and much cheaper.  Look at the newest Sony “DT” lenses, like the excellent 35/1.8; its performance in some ways is superior to the (equivalent FF coverage) 50/1.4, which is better built, but a little outdated and more expensive.  So what I’m trying to say here is; just because a lens was designed for a smaller sensor, doesn’t mean it’s inferior to a full frame compatible lens.

Below are two crops from full size images, the top crop is from the Sony 16.2mp A580 and the bottom crop from the Sony 24mp A900. The lens used is the Tamron 60mm F/2 macro, which is for APS-C cameras only.  Note; I also tested the Sigma 10-20mm F/4-5.6, which responded about the same way as the Tamron.  I matched both APS-C and full frame capture areas by moving the camera and tripod, that’s why the perspective is different, and done this way replicates a 24mp APS-C sensor.  Bracket focusing (focus point is the “Grand Canyon” dream catcher on the cap) was used until the sharpest image was produced for each camera.  The A900 APS-C size capture feature is turned off of course.  Both images are from RAW.  The A580 crop has been upsized to match the A900 size, which makes it easy to see the differences.  The A900 has a slight disadvantage here, as the final capture area was a little smaller than the A580, but not really enough to be noticeable. It may look like there is a depth of field issue at the top of the cap, but that’s not the case, it’s the smaller detail in that areas that’s more apparent with the 24mp sensor, that’s why I used the cap with a fine weave.  I used F/5.6, 1/4 sec, WB 3100k trimmed to M3, ISO 200.

Nothing much that’s newsworthy, so another file photo from the A700.

Here’s another sample image using the old and crummy Sony A700, now with a broken mirror.  The lens used for this architectural shot was the (also old and crummy) Sigma 10-20mm lens, which I still use and love.

This image was taken using five off-camera flashes, which wasn’t really enough, but that’s all I had at the time.  I placed one flash overhead, close to the camera side, and aimed it over the foliage towards the curved soffit above.  The next flash was placed on the lower patio area, fairly close to the ground by the wall, and pointed towards the foliage to bring out the tile texture and plants.  Also in this same general spot, but farther back (still out of view by the wall) is another flash that’s placed higher up, and pointed up to the curved soffit. On the next level down there’s another flash close to the wall by the spa, and pointed at the house wall with the stairs, you can see the shadows created by this in the larger version, click the image to check it out.  The final flash unit is to the right of the patio table on the lower level, out of view, and pointed at a tree and some foliage, but I ended up cropping this out as the wind was very strong causing too much blur, and I ended up not liking the composition, so that flash was wasted.  I darkened the area from the flash to match the light value of the rest of the right side.

I could’ve used a couple more flashes, or some powerful strobes.  I almost missed this shot as I was running back and forth trying to adjust the lighting placement and intensity while the best light was quickly going away, that’s the problem with doing a shoot without an assistant.

For the interior, I re-shot the living room area, firing a flash though the windows to light the backs of the chairs etc, and using two more inside the house, you can see the shadows from this set-up.

To finalize the image, I replaced the windows in the living room with the properly lit set and did the usual shadows, highlights, rotation and perspective (key-stoning) adjustments and some heavy noise reduction (the original image was a little underexposed, so raising the exposure in post processing increased the noise level). That issue isn’t the fault of the camera because it doesn’t have good high ISO ability, it’s because the camera operator didn’t
do his job.  The full image is a little soft, but shows well in my opinion.

Specs for the shot are; F/7.1, ISO 200 1/1 sec, about 14mm (21mm equiv) focal length after crop, and I think all flashes were at half or full power.

4/20/11

Don’t wait for a phantom camera or lens.

Famous photo house flirts with disaster.

Since I enjoy photographing homes and architecture in general, and reading about great photographers, I thought I’d put together a little background information on one of the most famous house photographs ever taken, the Case Study house #22, (Stahl house).  What really made this house famous was Julius Shulman’s 1960 photograph, shown in B&W, inset.

4/17/11

All four 70-200mm F/2.8 lenses compared, and Sony DSLR news.

Click for 70-200mm comparison page

4/16/11

Sony A390 soon to be obsolete, and thoughts on other stuff.

4/14/11

New ultra wide-angle lens from Sony coming soon?