New camera necessary to improve image sharpness?

[vegematic]

I have a Canon A610 that is nearly five years old and is my first digital. I love it but lately have been wanting sharper images and have not been able to get them. It is a 5mp camera that lacks RAW mode and image stabilization. I frequently use pre-set shooting modes (e.g. landscape) but have been increasing my use of manual settings. I have and sometimes carry and use a tripod. I process my images using Photoshop Elements 4 and to sharpen my images I use the "Unsharpen" filter at about 0.7 or 0.9 pixel (suggestion of a photographer friend but I don't know why he suggested it). I don't know whether I or my camera is the limiting factor at this point. Here is a link to some sample images that hI took this summer with the camera. Click on each image to see a larger view. These images are unprocessed so you can see them as the come off the camera.

So my question: Is there more I can be doing either at the camera or in processing to improve image sharpness or should I be thinking about a new camera with more pixels, IS, and RAW format?

I'm interested in the CHDK that was mentioned in Elizabeth's "bridge camera" thread, would that help?

-vegematic

 

[JohnL]

Switch your aperture range to f/8 - f/11. These apertures yield the optimum image sharpness and contrast for most lenses. Your aperture selections of f/2.8, f/3.2 or f/4 are wide open or nearly so and will result in 'softer' images. If you are using a tripod then your shutter speed is immaterial unless you include some sense of motion in your frame. Also get a remote shutter release (if your camera accepts one). Even pressing down the shutter button on the tripod mounted camera can lead to camera shake, thus rendering less than crisp images. If your camera will not accept a remote shutter release, use the shutter delay (self-timer) function. The delay will give the camera time to stabilize before it takes the shot.

Start with a good sharp image and then you can post-process it any way you like. But it's harder to post-process sharpness into a soft image.

JohnL

 

[DougPaul]

I have a Canon A610 that is nearly five years old and is my first digital. I love it but lately have been wanting sharper images and have not been able to get them. It is a 5mp camera that lacks RAW mode and image stabilization. I frequently use pre-set shooting modes (e.g. landscape) but have been increasing my use of manual settings. I have and sometimes carry and use a tripod. I process my images using Photoshop Elements 4 and to sharpen my images I use the "Unsharpen" filter at about 0.7 or 0.9 pixel (suggestion of a photographer friend but I don't know why he suggested it). I don't know whether I or my camera is the limiting factor at this point. Here is a link to some sample images that hI took this summer with the camera. Click on each image to see a larger view. These images are unprocessed so you can see them as the come off the camera.

Unfortunately the html instructs the browser to scale the images to fit the current size of the browser window--for proper evaluation, the images have to be at 100% scale--one image pixel per screen pixel. I had to download the originals to be able to view them at 100% scale using one of my local image viewers. (At 100% scale, the images are significantly larger than my screen.)

So my question: Is there more I can be doing either at the camera or in processing to improve image sharpness or should I be thinking about a new camera with more pixels, IS, and RAW format?

IMO, the images look reasonable for a compact camera.

I'm interested in the CHDK that was mentioned in Elizabeth's "bridge camera" thread, would that help?

CHDK may enable you to use RAW format to get better final resolution. Some in-camera processing (particularly noise reduction) tends to reduce the resolution. Try several different settings of sharpening--the best settings may be different for different images. RAW images are inherently soft--they pretty much all require sharpening. Post-processing to remove chromatic aberration can also improve apparent sharpness.

My suggestion is that you try RAW format. Some of the somewhat larger sensor compact cameras may be a bit sharper (more than 10 MP doesn't buy you anything in a compact camera--more MP means smaller pixels), but if you are really serious then consider a full-frame* 35mm DSLR with high quality lenses. And if you are really, really serious, then consider medium-format digital or film cameras ($$).

* Full-frame (eg Canon 5D or 5DII) is better than crop-frame (eg Canon Digital Rebel T2i or 60D). Larger sensors give you larger pixels which reduce the effects of diffraction and lens imperfections.

Doug

 

[DougPaul]

Switch your aperture range to f/8 - f/11. These apertures yield the optimum image sharpness and contrast for most lenses.

This is good advice for 35mm cameras with full size sensors, but for not compact cameras. (I've usually seen f/8 listed as generally being best, but close enough. It depends on a number of factors including pixel size and lens quality.)

The sensor in the A610 is a factor of 4.7 smaller than a 35mm sensor which results in much smaller pixels (2.8 microns for the A610). Therefore, one has to use a larger aperture to minimize lens diffraction induced loss-of-resolution and the optimum f-stop is smaller (larger aperture) than on a 35mm camera. In fact, the range of allowable apertures on this camera is f/2.8-f/8. These cameras are programmed to use larger apertures wherever possible to minimize the diffraction.

FWIW, compact cameras have greater depth-of-focus than 35mm cameras for the same f-stop because the lenses are physically smaller.

The review at http://www.imaging-resource.com/PRODS/A610/A610A.HTM includes a study of the image resolution.

Doug

 

[JohnL]

These cameras are programmed to use larger apertures wherever possible to minimize the diffraction. Doug

Hmmm, not really. The link you provided shows that the camera will program larger apertures for Portrait settings and smaller apertures for Landscape modes. The camera will set the aperture to various settings per pre-set creative apertures depending upon the type of Image Zone selected by the user. Creativity and aperture/focal length limitations appear to trump diffraction. And quite honestly, if your photography is limited to an occasional 8x12 or 11x14 print and photo sharing across the web, you'll never notice diffraction issues.

By taking a look at the sample images that were provided, we can see that they are all Landscapes. That tells me where the user's preferences lie.

Other settings that were not touched on were the compression and resolution settings. These will alter image sharpness as well.

JohnL

 

[nartreb]

The sample images all look pretty sharp to me - certainly nothing you'd notice at a reasonable print size.

(Hey DougPaul, this could be due to Apple doing dynamic coding for different browsers, but I don't see any scaling HTML around the images; the links are direct to JPGs. If your browser is auto-resizing, it should give you the option to view full size - usually just a click on the image.)

There are a couple shots where the focus is not great really close but good really far, or vice versa. When using a tripod, try manually selecting the smallest aperture available. You should also use center-point focusing to pick the focal plane that will maximize depth of field. (Google for "hyperfocal distance".) But your camera is already doing a good job of a basically impossible task, focussing everywhere at once.

At full size I can detect a tiny bit of chromatic aberration in some of the shots, which a much more expensive lens would probably remove, but it's pretty hard to detect already.

 

[DougPaul]

(Hey DougPaul, this could be due to Apple doing dynamic coding for different browsers, but I don't see any scaling HTML around the images; the links are direct to JPGs. If your browser is auto-resizing, it should give you the option to view full size - usually just a click on the image.)

I thought the auto-resizing was off (some images display as wider than the current browser window)--I'll check it later. (I also took a quick look at the html, but didn't spot anything.) In any case, by whatever method, one wants a 100% scaling to evaluate the sharpness of an image. Downloading the originals also gave me access to the EXIF which provided some of the numbers in my post.

When using a tripod, try manually selecting the smallest aperture available.

Until diffraction degrades the image. Typically ~f/8 for 35mm cameras, probably more like f/2.8 or f/4 for compact cameras (for a flat scene)... Reducing the aperture increases the depth-of-focus and reduces the aberrations, but also increases the "fuzziness" due to diffraction. The sharpest f-stop depends on pixel size, lens aberrations, diffraction, and the desired depth-of-focus.

Refs:
http://www.kenrockwell.com/tech/diffraction.htm
http://www.kenrockwell.com/tech/focus.htm
http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
http://www.luminous-landscape.com/tutorials/understanding-series/u-diffraction.shtml

Doug


EDIT: It does look like my browser was at fault for the automatic resizing--I rescind my earlier comments about resizing in the HTML. I had turned auto-resizing off in earlier versions, but the current browser does not offer it as an option in the preferences.

 

[nartreb]

Something I didn't notice earlier: there is a bit of noise visible at full size. Look closely at the sky (or its reflection) and you'll see some speckling. That's the achilles heel of small sensors.

(Either the monitor I'm using right now is way better than the one on my other machine, or else I was too preoccupied with checking the sharpness of edges to notice the noise in "flat" parts of the image.)

And now that I'm looking closely at the sky, I see a bit of vignetting in the corners too. For that you can blame the lens, but note that most lenses do have some vignetting.

 

[DougPaul]

Some additional info from the EXIF:

file    time      F    iso   eFL    FL     FLr
0032_1  1/60     3.2    50    34     7     7-29
0038_1  1/160    4.0    50    34     7     7-29
0048_1  1/60     2.8   135    34     7     7-29
0073_1  1/800    4.0    50    34     7     7-29
0077_1  1/160    4.0    50    34     7     7-29
0097_1  1/160    4.0    50    34     7     7-29
0098_1  1/200    4.0    50    34     7     7-29
0099_1  1/50     2.8    50    34     7     7-29

(eFL, FL, and FLr (FL range) are in mm)

So all pics except 48 (fallen log in the foreground) were shot at ISO 50. 48 was shot at ISO 135. At these ISOs, sensor noise should be pretty small. All images were shot at the minimum eFL of 34mm.

Some consider some vignetting to be desirable in some images--it tends to draw the eye away from the corners. Vignetting also tends to be reduced at smaller apertures and longer focal lengths.

Doug

 

[lx93]

Should I be thinking about a new camera with more pixels, IS, and RAW format?

YES! More pixels isn't always automatically a good thing, but there have been innumerable improvements since the A610. Do use MANUAL CONTROLS for ISO, shutter speed and aperture; to compare, photography in program mode is about as productive as doing a Presi Traverse bare-booted in February.

A few suggestions for you to consider:

A)
Point-and-shoot w/ MANUAL CONTROLS:

New:
1)
Nikon P7000
http://www.bhphotovideo.com/c/search?Ntt=p7000&N=0&InitialSearch=yes

2)
Canon G12
http://www.bhphotovideo.com/c/search?Ntt=g12&N=0&InitialSearch=yes

3)
Canon S95
http://www.bhphotovideo.com/c/search?Ntt=s95&N=0&InitialSearch=yes

4)
Panasonic LX5
http://www.bhphotovideo.com/c/search?Ntt=lx5&N=0&InitialSearch=yes

Used:

Canon G10, G11
http://washingtondc.craigslist.org/nva/pho/2089046454.html

Canon S90, S80
(~1/2 the size of the G10/G11/G12 series, but no optical viewfinder and you have to slog through menus instead of buttons)
http://washingtondc.craigslist.org/doc/pho/2095449027.html

Panasonic LX3
http://washingtondc.craigslist.org/doc/pho/2085911060.html

Of course, if you want something even better, here are the next 2 options:

B)
Nikon D90 for $739 to $799
http://www.adorama.com/searchsite/default.aspx?searchinfo=d90,+body

C)
Nikon D300s for $1,449
Weather-sealing is the biggest improvement over the D90. No, you wouldn't want to take a bath with it, but you can shoot worry-free if snow flurries are coming down.
http://www.adorama.com/SearchSite/Default.aspx?searchinfo=D300s, body

With both B & C, you would need to buy a lens. But for landscape shots, you can pick up a 18-55mm for DIRT CHEAP ($100-ish) or get a better 16-85mm VR for $400 used, $600-ish new.

If you want something to zoom in on peaks or to capture partners' expressions of regret at not spending $ on 'fancy' gear like crampons as they slide on the ice, the 70-300mm VR ($389 new when bought w/ either B or C) is a no-brainer.