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powernapper May 3, 2006 11:33 AM

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I'd be grateful for any thoughts regarding this pic. 1/160th sec, F2.8, ISO80, 3:2, chrome, sharpness hard, aperture priority.

Pic has been cropped and saved for web. No other processing.

Is this amount of chromatic abberation typical of this camera?

Many thanks in advance.

jphess May 3, 2006 12:24 PM

That picture does not display very well on my monitor. And that is partly a problem because of having to reduce the size and quality in order to be able to display the picture on the Web. Chromatic aberration seems to be an unpredictable phenomenon that is affected by a number of factors; quality of light, amount of zoom, etc.. If you are starting to panic, DON'T. The Fuji S9x00 is a wonderful camera. But every photo isn't going to be a masterpiece.

algold May 3, 2006 5:34 PM

It's hard to comment on this particular image, because of its small size. It's not in focus and it lacks contrast. Either the image quality severely degraded during the resizing, or the exposure was not right in the first place, may be it's my monitor.

Generally, CA may appear in the areas of high contrast and you do have a lot of straight dark vertical objects in this pic. So, it can happen in this kind of picture.

Personally, I would not recommend to use 3:2 image size, chrome setting and hard sharpness at the same time - they can affect the final quality of your images.

3:2 is convenient for printing on paper of standard sizes without borders or image cropping, but on this camera this setting is only available in Jpeg normal (i.e. the Jpeg compression is quite high and this can add the jpeg comression artifacts to your image). The memory prices are low now and IMO it's better to buy a larger memory card and shoot in 9MPFine than cripple your camera shooting in lower resolution and/or quality.

Chrome mode is just a combination of high contrast and high saturation settings. With some subjects you can get images with an additional punch, with others you wouldn't see any difference, or you can loose details in highlights or shadows and the colours can look unnatural.

Hard sharpness setting involvesa lot of in-camera noise reduction and sharpening. If you do these operations on your computer you have more creative freedom and can get much better results.

Just my $0.02.



jphess May 3, 2006 5:57 PM

Those are all excellent points, Alex. I experimented a little with hard sharpness and the chrome color setting, but found that I got the best results by leaving everything in the "normal" positions. Then, if I decide that I need to make adjustments I just do that in Photoshop.

powernapper May 4, 2006 5:58 AM

I just love this forum! So much help in such a short time. Thank you.

On reflection, all of your advice helps to explain the recent deterioration of my photography. I said to my wife just a few weeks ago "I've never taken so many bad shots in such a short time".

The pic has not been re-sized, just cropped to show the area where CA was at its worst. The main subject of focus (far end of the pier) has been cropped off, so the out of focus area shown is down to depth of field (f2.8). Sorry for not having the forethought to mention this earlier. The appeal of this shot (for me) was the mood of the misty day, so the contrast was never going to be high.

I didn't realise that 3:2 (until now my favourite aspect ratio) was only available at lower res., this explains why suddenly everything has been 72dpi !!! Many thanks again.

So, from now on I'll stop fiddling with the settings, re-set everything to 'standard', and get back to enjoying my Fuji.

Sincere thanks to you all.

JimC May 4, 2006 6:47 AM

It's normal to see more CA in out of focus areas in an iimage when there is a lot of contrast (tree limbs against a white sky, etc.).

Not only was the weather a bit bad, but to my eyes, it looks like you missed the focus, contributing to the problem. Without looking at a larger image, it's hard to say for sure.

If you look at the poles on the far right of the image, they're sharper than the ones further left and closer to the camera from what I can tell. You'll also see more CA in the portions further left (and more out of focus).

I'd make sure you've got the desired focus point selected (or lock it to center only). Your camera has multiple AF modes to choose from. The Area Select option lets you pick the focus point (rather than the camera locking on something you may not want as your focus point). Or, you can set it to always use the Center Focus.

Either way, half press and make sure the camera achieves focus lock, then reframe and press the shutter button the rest of the way down to take the shot.

Shooting at wide open apertures can also contribute to CA, and reduces depth of field. In this case, lighting wasn't optimum. When lighting permits (keeping an eye on shutter speeds), I'd try to stop down just a tad (versus shooting wide open at f/2.8 ) to help out in similar conditions.

jphess May 4, 2006 10:50 AM


The 72 PPI is not the issue here. A standard 3:4 aspect ratio image from the 9000/9500 years 3488x2616 pixels. Those numbers change in the 3:2 aspect ratio, but the totals are about the same. In the 3:4 mode, even if you use the normal rather than the fine setting the dimensions of the image are the same. If you multiply those dimensions out, it totals about 9 MP. The 72 PPI setting is what the 9000/9500 chooses to report as the size of the JPEG images it takes. And that just means that at 72 PPI the images would be whatever that dimension is. If I work with raw images from the camera in Adobe Camera Raw those images are reported at 240 PPI. The image is not any bigger or smaller, as far as the number of pixels, only the dimensions change because the pixels are "pushed" closer together making it easier to get higher quality prints.

What does make the difference is the amount of compression and the camera applies when it saves the file. The normal mode is much more aggressive, and JPEG compression is very destructive. If you are looking for the absolute highest quality, you want to shoot in 9 MP Fine mode with all in-camera settings (color, sharpness, contrast) left at their default. I think you'll find that you will get a high percentage of successful images that way. But since the camera doesn't see and interpret light the way our eyes do, sometimes a little postprocessing is required. Every roll of film you ever sent in for processing was postprocessed. All automated printing services try to average out every print they do. That's why, if you are like me, you often had to order reprints the get the color that you wanted. Now, with digital photography, you can have complete control of the entire process you want to do that.


powernapper May 5, 2006 9:55 AM

1 Attachment(s)
Still reading your advice. Thanks.

We use a variety of point-and-shoot digital cameras at work, some of which "appear" to display their files at a higher res. hence my confusion. Thanks Jim for the explanation, all makes sense now.

I've attached a gif of the full frame. Obviously it's not much use other than to show composition.

I still have the concern that as I shot at f2.8, thereby using more of the lens, could the CA be a characteristic of the lens? As JimC has said, the CA is definitely worse on the poles nearer to the camera, ie the edge of frame.

jphess May 5, 2006 10:52 AM

I don't have a lot of understanding about the CA problem, but it is my understanding that it is more prominent needed the edges of your image. I haven't noticed it enough in most of my pictures to really get in and study it. But, in my opinion, considering the relatively small section of the image that you posted originally, I don't think the CA is prevalent enough to be concerned about. I wonder what it would have been like if you had zoomed in on the section and then posted the full image.

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