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Old Mar 7, 2010, 7:15 AM   #11
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..a technique...to balance exposure with my camera..feedback..Ö Kodak Z1012is -Manual mode on this camera allows adjustment of aperture, shutter speed, ISO, and the camera automatically adjusts exposure compensation...does provide an exposure histogram but frankly I donít get it. ....any experience you could share with similar technique!
Kevin,

I have a Kodak Z1012 and a Z712, in regular use. I bought the Z1012 as a backup for the Z712 which I prefer (bit smaller, bit lighter, slightly less fussy menu interface). Generally I leave them set in aperture priority, choosing an appropriate aperture, but twiddling aperture or occasionally ISO to get an acceptable shutter speed. I use shutter priority for action shots.

However, the best feature of these two cameras, not mentioned yet in this thread, and not even believed by some, is that in A,S,P modes they have a 'live preview' showing continuously in the electronic viewfinder, which is usually shielded by your face from extraneous ambient light. Note that this feature is absent from (M)anual mode (and EV adjustment is not available in that mode).

So I seldom leave the aperture/shutter combination to the camera's metering system; I assess it myself in the viewfinder and adjust it using EV correction until I think the exposure is correct, minimising blown highlights and maximising shadow detail, sometimes using the histogram for assistance, until I think the image 'looks just right'.

If the 'quickview' feature is turned on, after pressing the shutter release there's a few seconds' display of the just-taken image, replacing the live view you've just seen, which will still be there afterwards. If they didn't look the same and acceptable, I try again with the EV adjusted. If I still haven't found a suitable exposure, I turn bracketing on and take it again.

Thus these little, cheap cameras give me the capability to adjust the final image to my visual taste before I push the button. This is much more satisfying than believing the meter and adjusting its idea to match mine later in the darkroom (in the olden days), or latterly in digital post-processing.

So I recommend, Kevin, that you try this technique on your Z1012. Note that you need to half-press the release once or more first for each shot to allow the metering and focus to settle down.

First turn on 'Quickview' in the menu system. Look through the EVF of your camera at an 'average' sort of subject, and try, in each of 'A', 'S' and 'P' modes, adjusting the 'EV compensation' up and down, half -pressing the release after each adjustment. You can do all this without taking the camera from your eye. In 'P' mode, the camera will choose a shutter/aperture combination for you, but you can still twiddle EV. You'll see the image lighten and darken as you adjust the exposure.

Now turn to 'M' mode, and you'll see this viewfinder image adjustment feature disappears. Go back to 'P', 'A' or 'S' modes, adjust the image, take a shot, and confirm that the 'quickview' that pops up for a few seconds is closely similar to what you saw before you pushed the button. You can try turning the histogram display on as well, if desired.

I just got out my Z1012is and tried all this through a window, so I know it works! I hope it's clear enough. Good luck!

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Old Mar 7, 2010, 12:13 PM   #12
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...However, the best feature of these two cameras, not mentioned yet in this thread, and not even believed by some, is that in A,S,P modes they have a 'live preview' showing continuously in the electronic viewfinder, which is usually shielded by your face from extraneous ambient light. Note that this feature is absent from (M)anual mode (and EV adjustment is not available in that mode).

So I seldom leave the aperture/shutter combination to the camera's metering system; I assess it myself in the viewfinder and adjust it using EV correction until I think the exposure is correct, minimising blown highlights and maximising shadow detail, sometimes using the histogram for assistance, until I think the image 'looks just right'.
I believe that what you described above is true for every P&S (and now the mirrorless models - micro 4/3 and the NX10 from Samsung up to this point)...you get what you see. This is indeed very handy and with the proper use of the live histogram, one can pretty much get the shot right the first time (we are talking correct exposure here). I'm not familiar with the Kodak models but I have a Sony R1, which incorporates a feature I haven't seen in any P&S so far, called the Zebra pattern. Basically, if it's turned ON, this feature will create a zebra-like pattern on all highlighted areas of the image (as you half-press the shutter release button to pre-focus and exposure set - so before you actually take the picture). As you turn the back wheel, you can see the zebra patter spreading or getting reduced. This allows you to very accurately set the perfect exposure every time.
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Old Mar 7, 2010, 1:09 PM   #13
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...what you described..true for every P&S...you get what you see...very handy and with the proper use of the live histogram, one can pretty much get the shot right the first time (we are talking correct exposure here)...

...Sony R1, which incorporates...Zebra pattern. ...on all highlighted areas of the image...This allows you to very accurately set the perfect exposure every time.
Yes, but only with a reasonable electronic viewfinder is it possible to use the live preview without interference from ambient light. Even on modern bright LCD screens, in many circumstances, especially in bright conditions with difficult, partly back-lit subjects, one sees a nice reflection of oneself rather than the preview image. I've trained my octogenarian mother-in-law to do it this way on my son's cast-off 2005 Sanyo S4, which has nice '+' and '-' buttons next to the LCD which adjust exposure and not just the screen brightness, but she's often defeated by ambient light.

As for 'correct' and 'perfect' exposure I often find there may be a 'best' one but none is quite ideal. Only the photographer can judge where the most important bits of image lie.

I haven't seen the Zebra pattern, but I think I'd want to be switching it on and offa lot, because I'd want to see whether the desired detail in highlights or shadows was adequately displayed.

Anyway, if folk can adjust their exposure by eye so easily, why is so much effort expended on metering and estimating it so carefully, and why are the cameras called 'point & shoot', when anyone could be doing better by 'point, adjust to taste, and then shoot'? I've owned and used 7 digicams, and only on these Kodak superzooms have I had the features (EVF with full eye-level exposure adjustments) to use this method effectively and routinely.
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Old Mar 8, 2010, 9:58 AM   #14
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...
I haven't seen the Zebra pattern, but I think I'd want to be switching it on and offa lot, because I'd want to see whether the desired detail in highlights or shadows was adequately displayed....
You really don't have to switch it on/off. As you reduce the exposure, the zebra pattern diminishes so you can actually make it disappear. The thing is, not all highlights are bad and need to be controlled. So, it is up to the photographer to make the determination as to whether the exposure needs to be dropped further to reduce highlights. The zebra pattern does not interfere in the overall display of the image. It's just a very clever system!
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Old Mar 15, 2010, 6:52 AM   #15
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To wrap this up, lets talk about aperture and how it will affect your exposure. Since your camera is a P&S, we know you will not obtain a real shallow DoF, no matter how wide you keep the aperture. In fact, unless this is really your intention, I would not keep the aperture at its widest value because that's not ideal for sharpness. The wider the aperture, the less sharp the image will become.
How's that?

In one of Gordon Laing's reviews that I read recently at cameralabs.com, he stated (and physically demonstrated) that a smaller aperture (higher f-stop number) creates more diffraction than a wider aperture (lower f-stop number). This seems to contradict your statement above. Could you clarify?

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Mark
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Last edited by Mark R.; Mar 15, 2010 at 7:06 AM. Reason: Close quotes
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Old Mar 15, 2010, 11:22 AM   #16
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Gordon Laing's reviews...smaller aperture (higher f-stop number) creates more diffraction than a wider aperture (lower f-stop number). This seems to contradict your statement above. Could you clarify?
I expect Tullio will answer for himself in due course, but in the meantime, the statement above is true, but not directly relevant to the issue under discussion, namely 'depth of field', i.e., how far apart the nearest and furthest objects are that are acceptably in focus.

Diffraction effects increase as you get towards smaller and smaller holes in the lens (apertures), because as things get smaller you get proportionally closer and closer to the wavelength of light, so that tiny bits of light get so important they interfere with each other.

However, on the scale usually practised by most of us in photography, one of the important aspects, 'depth of field', (how much of the image is in focus) gets better and better the smaller the hole in the lens. This means smaller in absolute terms, in millimetres diameter, not in terms of focal length (f-number), because f/16 at typical focal lengths on a point and shoot digicam is a very small hole compared with f/16 on an 8inchx6inch plate camera.

The greatest depth of field you'll get is a pinhole camera, with a tiny pinhole as lens, with the biggest possible sensor you can put behind it. But you'll need a very long exposure. If you want a very shallow depth of field, you need a big hole, and the bigger the camera, the bigger the hole will be for a given f-number. The aberrations in the large area of lens become much more important than diffraction, because every lens has imperfections, compared with an idealised pinhole.

I hope this clarifies it a little.

Alan T

Last edited by Alan T; Mar 15, 2010 at 11:37 AM.
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Old Mar 15, 2010, 11:34 AM   #17
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In one of Gordon Laing's reviews that I read recently at cameralabs.com, he stated (and physically demonstrated) that a smaller aperture (higher f-stop number) creates more diffraction than a wider aperture (lower f-stop number). ...
Yes, this is true but diffraction is more evident on DSLRs where one can stop down to f22 or even further depending on the lens. On most P&S (if not all), the smallest aperture is f8 and even though theoretically it may translate into f16 or f22 in DSLR terms, due to lens construction and how it works with the smaller sensors, diffraction at f8 is practically non-existent. Also, I did not state that a wider aperture would or would not create more diffraction. What I said was that wider apertures will tend to produce softer images (and one must keep in mind that some of the newer cameras come equipped with very good lenses, which will produce reasonably sharp images at their wides aperture - but still not a very shallow DoF). Hope this clarifies things a bit.
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Old Mar 16, 2010, 6:59 AM   #18
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Hi,

Until I read Tullio's second-to-last sentence, I thought I'd understood the matter, but now, I'm as confused as ever.

I thought that you guys equate soft to shallow DoF, and sharp to deep DoF. In this case, the sentence "wider apertures will tend to produce softer images" would have made perfect sense.

But then, Tullio wrote: "... very good lenses, which will produce reasonably sharp images at their wider aperture - but still not a very shallow DoF".

So, from the above two postings, I gather that...
"Sharp" is neither synonymous with "little diffracted" nor with "deep DoF", and
"soft" is neither synonymous with "diffracted" nor with "shallow DoF".

What, then, is meant with "sharp" and "soft"?

And if diffraction does not really play a role at F8, as Tullio maintains, why was Gordon's F8 image fuzzier than the F4 image? According to Tullio, an F8 image should be sharper!

Sorry, but I'm now truly and well confused between DoF, sharpness and diffraction.

Regards,
Mark
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Old Mar 16, 2010, 7:56 AM   #19
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...I thought that you guys equate soft to shallow DoF, and sharp to deep DoF. In this case, the sentence "wider apertures will tend to produce softer images" would have made perfect sense...


There are several ways in which your images can be rendered too unsharp for purpose. Here are a few...
  1. Camera shake;
  2. Incorrect focus, with an aperture large enough make it a problem, i.e., not enough depth of field;
  3. Inadequate lens quality;
  4. Inadequate sensor quality;
  5. Final viewed image enlarged too much, so that any of the above come into play, poor post-processing, poor viewing equipment e.g., wrong spectacles (eyeglasses).
  6. Photographer too fussy about image quality. For example, my wife is very happy with images that are much too unsharp for me to find tolerable, if she likes the content of the image.
Confusingly, in historic photographic tradition, 'soft' also meant "low contrast", as opposed to "hard" (high contrast), when applied to images, film, and printing papers.
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Old Mar 16, 2010, 9:13 AM   #20
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Most lenses seem to obtain their maximum sharpness at a couple stops up from maximum aperture. So a lens with f/2.8 max would likely have its best sharpness at f/5.6. Sharpness is measured as a function of edge contrast (usually). A picture can be very sharp at the point of focus, but still have shallow DOF.
Finally, diffraction is a function of lens opening, not necessarily f/ number. The f/number is relative to the focal length of the lens, so f/8 on a small sensor camera, could very likely have the same absolute diameter as f/22 on a DSLR.

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