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08-28-2007, 10:57 AM   #1
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Achieving Sharpness

I am a new user of a k110d – so far I am really enjoying this camera. I have been working on exposure for more creative expressions, working in aperture and shutter priority modes to control depth of field and convey motion.

I must plug the “Understanding Exposure” book by Bryan Peterson – it is an excellent resource and should be considered mandatory reading for any new enthusiast!

That said it filled my heads with all these ideas that I have been exploring and I have been happy with the results in terms of “lighting exposure” and general depth of field, but am really struggling getting sharp focus (or properly focused) pictures and am looking for tips.

My usual subjects are my kids, portrait work and action shots in a wide range of lighting – mostly outdoors.
Bottom line –set the camera on f11+ with bright light and fast shutter and the pictures are sharp – wider aperture and/or moving subjects and they fall out of sharpness almost every time.

So to be more specific:

ISO
I have been letting the camera set iso – noticed all my shots are coming in at 200 – even low light or shadows based subjects. Knowing the kit lens is not a fast one, would pushing up the ISO to 400/800 allow me to maintain a more shallow dept of field, wider aperture and a faster shutter to prevent motion blur?
Shutter Speed
What is really the “practical” limit to a hand held shot to come in sharp without introducing camera shake or motion blur introduced by the camera holder?
Metering and Auto Focus and zoom
Does your metering setting effect auto focus? In other words does the autofocus in the camera look at the larger area on the center weighted over the spot metering setting? Are better focusing results achievable with either or matrix for that matter or is there no correlation?
“Portraits” of moving subjects (kids under 4 never sit still) with a shallow depth of field
How does one do this and get a tack sharp shot - luck? F11 + on the kit lens works well but there is still a lot of background in the shot unless the whole thing is completely staged. I am looking for a way to pull of what look portrait level quality of sharpness without all the background needing to come along for the ride with a high fstop. Is this a lens issue? Would I be better off with a fast fixed 50 to 70 to get these types of shots nice and crisp?
Any tips on achieving sharpness anyone has would be very much appreciated

Thanks in advance!

~derek

08-28-2007, 11:10 AM   #2
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Something I've struggled with and not found the answer to completely. Helps:
a) lens a few stops less then wide-open is mandatory unless it's a super expensive lens.
b) don't rely on shake reduction to push shutter speed. Rule of thumb for shutter speed is 1/focal-len min for stationary subjects, 2x 1/focal-len if the subject is moving, 3x 1/focal-len if [edit] YOU are moving. Yes, shake reduction helps, but I'm -way- too shaky as a 2month novice to allow even it to be effective in giving me sharp shots.
c) as fast a shutter as you can, regardless.

Don't get me wrong. I'm floored when I get a keeper shot handheld at 1/60 or 1/30 sec using my 300mm lens.But that's few and far between.

...now if I'd only listen to my own advise... ...I might not have so many throw-aways I thought would be keepers from my trip to Tanzania...

Last edited by m8o; 08-28-2007 at 01:00 PM.
08-28-2007, 11:16 AM   #3
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QuoteOriginally posted by m8o Quote
b) don't rely on shake reduction to push shutter speed. Rule of thumb for shutter speed is 1/focal-len min for stationary subjects, 2x 1/focal-len if the subject is moving, 3x 1/focal-len if the subject is moving. Yes, shake reduction helps, but I'm -way- too shaky as a 2month novice to allow even it to be effective in giving me sharp shots.
He has a K110D, so he won't be relying too much on the shake reduction

BTW, SR is nice, but for most of us not a critical feature of the camera.
08-28-2007, 11:30 AM   #4
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1) iso sensitivity up to 1250 is very usable. turn off noise reduction unless you're shooting a long exposure and need that extra frame to remove hot pixels. use noise ninja or something comparible if shooting high iso (high noise).

2) 1/focal length. if you're shooting with a 50mm, then 1/75 would be the lowest you could go without worrying about shake. some people can go lower than 1/fl because they have very steady hands or are lucky.

3) you can link af points to metering points i think; however i wouldn't. spot metering will lock you to the center af point.

4) f11 doesn't mean your picture will be sharp. your options are a wide aperture or a high iso sensitivity to get the shutter speed up. to get the most out of your camera/glass, disable sharpening on the body and do it on your computer when post processing. if you have photoshop cs3, smart sharpen with around 130% and .3 radius; if you have cs2 or earlier or light room use an unsharpen mask.

08-28-2007, 11:38 AM   #5
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QuoteOriginally posted by superfuzzy Quote
He has a K110D, so he won't be relying too much on the shake reduction

BTW, SR is nice, but for most of us not a critical feature of the camera.
?? I thought K110 had it and K100 didn't ... then 100 Super came out that had it too... No?
08-28-2007, 11:40 AM   #6
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QuoteOriginally posted by attack11 Quote
3) you can link af points to metering points i think; however i wouldn't. spot metering will lock you to the center af point.
Ah.... really? That might be behind me having less then stellar AF performance then! I need to do my vacation over and re-shoot the whole thing!!! Or am I making a mistake of what you mean... as you talking about AF-S , or the advanced option of linking the meter point to the AF point?

Last edited by m8o; 08-28-2007 at 11:46 AM.
08-28-2007, 11:45 AM   #7
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QuoteOriginally posted by attack11 Quote
2) 1/focal length. if you're shooting with a 50mm, then 1/75 would be the lowest you could go without worrying about shake. some people can go lower than 1/fl because they have very steady hands or are lucky.
Luck does not help. It just doesn't run often enough to be useful.
I shoot between breaths, for example. If possible, and if I feel it (not always), I shoot between pulse beats too. I always hold my breath when I focus and it is not uncommon for me to gasp desperately for air once in a while when I can't obtain focus lock for longer time (handheld macro in open air)
08-28-2007, 12:20 PM   #8
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QuoteOriginally posted by m8o Quote
?? I thought K110 had it and K100 didn't ... then 100 Super came out that had it too... No?
You have it backward, the K100D has it, the K110D doesn't.

SLC

08-28-2007, 12:23 PM   #9
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QuoteOriginally posted by m8o Quote
?? I thought K110 had it and K100 didn't ... then 100 Super came out that had it too... No?
No I have the k100 and I have SR

Loving this thread BTW... learning a LOT! I really need to pick up that book!
08-28-2007, 12:46 PM   #10
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Get an external flash and bounce it off the ceiling for nice easy kiddie shots indoors. Solves every problem known to man. Even a friend with a Canon 5D can't get good kid shots without flash, it makes more difference than anything else. Don't compare with the results from the built-in flash, it will be far better.
08-28-2007, 01:10 PM   #11
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I don't see why you need f/11 to get a decently sharp image.

Focal Length: 21.0mm
F-Number: F/6.3
Exposure Time: 0.0166 sec. 1/60
Metering Mode: Spot
ISO Speed: 1600

This was with the kit lens. Unless you're pixel peeping, I would be pretty liberal to use the entire aperture range, especially while still learning about photography.

1) Opening the Aperture and Increasing the ISO will both allow you to have shorter (faster) shutter speeds, but only Aperture will also change your depth of field though. Just keep that in mind when you're composing the picture. 400 and 800 are perfectly usable on that camera. I wouldn't be shy to use 1600 on the K110/K100 actually.

2) Been answered

3) Your Auto Focus can effect your Light Meter (if you link focus point to light metering in the option). Light meter does not affect the performance of or the method used to Auto Focus.

4) F11 is supposed to give you a wider depth of field. Aperture is the only thing that controls your depth of field. If you want the shallow look, you MUST use larger apertures or learn how spends hours per picture on photoshop to duplicate the look. Composition is much more important than making sure the picture is tack sharp. General portraiture can benefit by having a little bit more softness to it (think of the typical studio glamour shot) anyways.
08-28-2007, 03:48 PM   #12
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Another thing to consider is your hand holding technique. Using proper techniques will improve the sharpness of your photos by reducing camera movement. With some practice you will probably find that you will be able to handhold shots at slightly less than the 1/focal length rule.

Proper Handholding Technique
Proper Long Lens Technique
08-28-2007, 05:07 PM   #13
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Derek,

Auto-ISO can be useful in a number of situations, but if you're trying to figure the camera out, I recommend that you take charge and tell the ISO to sit and stay! Set it on 200 or 400 and leave it there for a few days or a week and get familiar with the two primary controls -- aperture and shutter speed.

Neither aperture nor ISO has anything to do with sharpness. Aperture has a lot to do with depth of field, as you know. But if you shake the camera while you're shooting, well, aperture ain't going to help you out. You're still going to get a blurry picture. And using a faster or slower ISO doesn't make a photo sharp. Using a higher ISO may result in a noisy image, and noise can have the effect of making a photo seem less sharp. Actually, I would even say that the shutter speed in itself doesn't determine whether an image is sharp. You can shoot at 1/1000sec and get a picture that's not as sharp as it should be.

Sharpness is largely controlled by four things: stabilizing the shot, focus, lens quality, and post-processing.


First, you have to stabilize the shot.

I started to say "freeze the action," but that's not really the right way to put it. You need to freeze the relationship between the camera and the subject during the time of exposure. If you're shooting sports and the subject is, say, doing a somersault, then that means a fast shutter speed. But if you're shooting a mountain landscape at sunset, obviously the mountain isn't moving around, but you may need a slow shutter speed here to be able to take the picture without undue noise, and so you probably need to use a tripod.

How fast a shutter do you need to freeze the action for a moving subject or when you're holding the camera in your hands? It depends, but there is a fairly straightforward rule about this: Keep the shutter speed at least as fast as the reciprocal of the focal length. In other words, if the focal length is 200mm, then you would do well to set your shutter no slower than 1/200second.


Second, focus!

This is a negative factor, rather than a postive one. Focus is not the same thing as sharpness, but an out of focus shot can never be sharp. If you shoot a building at 1/1000s, you've got a nice stable relationship of camera to subject, but it's still not going to be a sharp photo if the camera isn't well focused. Depth of field can help here, but you have to get some crucial part of the photo into clear focus. Keep in mind that you should not usually be worrying about your images being grossly out of focus; you should be worrying about getting them as precisely focused as possible. In other words, a photo that's just slightly out of focus might look like it's not sharp -- but the problem isn't sharpness per se, it's that the subject was just a teeny tiny bit out of focus.

I find auto-focus pretty effective, at least for normal shooting, where there's enough light and a reasonable amount of contrast in the subject. I'm not one of those who thinks that auto-focus is for wimps. But there's no denying that in some situations -- say, when you're shooting macro -- manual focus often produces better results.

There's a lot more to say about this topic but I'll leave it at that for now.


Third, good lenses produce better results than bad ones -- and most lenses have a sweet spot.

There ain't much you can do about the quality of your lenses without spending money, but it's worth keeping in mind that some lenses are simply better than others. The acuity of the lens isn't the only thing that matters. Price matters to me! So does versatility, by which I mean that a 28-75 f/2.8 Tamron lens is worth more to me for the kinds of photography that I do than, say, a Pentax mid-range prime lens that might have better lens acuity. But the fact remains, lens A may simply be a better optical instrument at its best than lens B at its best.

It's also true that zoom lenses often have "sweet spots." The sweet spot is usually NOT at the extremes of the zoom. SO if you're shooting with the Pentax 18-55 kit lens, you might find that you get somewhat better (sharper) results -- other things being equal -- if you shoot around 35 or 40mm.


Fourth, post-processing makes a difference, too!

Finally, it should be noted that the data that the camera stores on your SD card may benefit from a little sharpening in your post-processing software. A little of this goes a long way, so be careful. One of our colleagues has a wonderful line in his sig: "We live in the age of over-sharpened images". I like Picasa (Google's free photo editor) but it doesn't allow me to control the degree of sharpening, and it invariably OVERsharpens the images. You should be aware that there is a significant difference between the way things look to you on your computer screen and the way that they look, say, in print. An image that looks a bit soft on screen will often print out looking really good -- and images that look tack sharp on the computer may be too sharp when printed.

So, to maximize your chance of getting a sharp image, make sure you have plenty of light, keep the shutter speed reasonably high and the ISO low, get the focus right, use your best lens in its sweet spot, tell the subject to hold still, use good technique when depressing the shutter (so you don't move the camera), and expect to add a little sharpening in post-processing. If you wonder whether your camera and/or your lens is capable of achieving sharpness, do some tests with a tripod and remember to turn SR off while testing.

__________



I'm ultimately more interested in taking interesting shots, with nice compositional qualities, good tonal range, well exposed shots, well focused shots, than I am with worrying about getting things tack sharp. For fashion photographers and commercial product photographers, anything less than tack sharp may simply not be acceptable. But for most of us, even those of us who are really serious about what we're doing when we have a camera in our hands, sharpness is just one of the components of an image, and it's usually not the most important one.

Hope this helps.

Will
08-28-2007, 05:23 PM   #14
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I have seen several references to aperture in this thread. Any rules of thumb in terms of aperture values and affects or aperture values for certain types of pictues?

Note: I have found this thread very interesting - thanks!
08-28-2007, 06:27 PM   #15
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QuoteOriginally posted by CallMeDerek Quote
I have been letting the camera set iso – noticed all my shots are coming in at 200 – even low light or shadows based subjects. Knowing the kit lens is not a fast one, would pushing up the ISO to 400/800 allow me to maintain a more shallow dept of field, wider aperture and a faster shutter to prevent motion blur?[/INDENT]
Are you using any exposure compensation, by any chance? The K100D (and therefore also the K110D) has a weird feature (I'd call it a bug, but it's in the docs, so it must be a feature) where if you set EV + or -, it will only use ISO 200 in AutoISO mode -- if you want a different ISO, you'll have to pick it manually.
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