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Monday
Jul142008

SCL Photography Podcast 4 - Taking Sharper Photo's

SCL PodcastThis one's a bit long folks - almost an hour, I got a bit carried away with what I've been doing, and the main subject of "sharper images" took a little longer than I thought it would. My apologies for some glitches in the audio during the first half of the show - I think my anti-virus was doing stuff in the background, and I didn't notice until I'd uploaded it. Enjoy!

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Show notes:





My Blog Posts Referred To In Podcast:

Noise ninja.

Photobackup.

HDR Still lifes.

Kodak HDR.

Photowalk 23 - Gosport Mini.

Picturenaut HDR.

Macro subjects on black.

Subject - Sharper Photographs (Script Notes)

Nothing more frustrating than getting home to discover shots that look crisp and sharp on your lcd screen look blurred on your pc or when you print them out - so lets talk about the three main causes - camera shake / subject movements, aperture / focal length choice, focusing issues, and post-processing. and how we can apply them.

Camera shake - we need to make sure our camera is solid! First and best choice is often a tripod - make sure its level and all the adjusters are tight. When buying one try and get one with a quick-release plate that fixes to the bottom of the camera, and remember that in strong winds even a tripod wobbles. I also often lay my camera on the ground, so I have an old woolly hat that I sit my camera on - but you can buy bean-bags, smaller tripods, etc to do the same job.

If hand holding, try and lean against a wall or tree, anything to brace your body so that you're not swaying. Look at how you're holding the camera, maybe brace the elbow of the arm that is supporting the camera against your chest. Don't squeeze the camera body, gently support it. Use your shutter delay to prevent movement from pressing the button, and try taking a deep breath, then exhaling as you take the shot or wait for the shutter delay to take the pic.

Subject movements - now our camera is solid, we need to think about the potential movements in our subject (or our camera if we're hand-holding) - people swaying, the wind blowing trees or grass, flags flapping, animals moving, etc - we need to freeze time, and we do this by increasing the shutter speed. You can't do this in auto mode - so go to programme, ap, sp or manual modes. - programme or ap are the best to start off with. To freeze our subject we need a fast shutter speed - 1/100th, 1/250th etc. But as we're increasing the speed, we're letting less light in (our pictures could underexposed) - so we might need to increase the aperture size by making the f stop number smaller, and / or increase the ISO settings - that is how sensitive the camera is to light. The higher the ISO, the faster shutter speed you can use, but this is at the expense of noise in the final image. I usually open up to my widest aperture first (f3.5) see if that works, then increase the ISO. If you're hand holding your camera also bear in mind that as you zoom in, camera shake is magnified, so you'll need an even faster shutter speed. In low light, and if your subject is in range, perhaps try a flash shot. If its a windy day, wait around for a few minutes for a lull, or make the movement of grass / trees an artistic choice and go to a slower shutter speed. Taking lots of shots helps! Your camera will normally try and warn you if it thinks that an image may be blurred - but ignore this if you're on a tripod!

Aperture / focal length choice. We're getting a bit technical here, but your camera, or lenses are optically sharper at different apertures and different focal lengths. Accepted wisdom is that lenses are sharpest around their middle aperture, but this does vary with focal length (how much you're zoomed in), so I don't worry about it too much.

What is worth thinking about is your DOF. This is how much of your subject will be in focus in terms of distance from the lens. So at larger apertures - f3.5, etc, your camera will have a smaller DOF - great for subjects where you want the foreground and background blurred (macro, portraits), and at smaller apertures (f13.5) everything will be in focus (landscapes). - Remember though that as you focus on things further and further away, at some point the lens goes "hyper focal", so everything beyond that point will be in focus anyway. Also bear in mind that as you're using smaller apertures you're letting less light in, so you'll have to use a higher iso to keep the shutter speed fast, which could lead to noisy pictures. (unless you use a tripod! or you and your subjects aren't moving)


So why might your pics be out of focus (assuming you're using auto focus) - understand how non-dslrs work - they look at contrast to work out whats in focus - so they have trouble with metallic things, reflective objects, things without edge contrast - try and focus on something else at the same distance, press shutter half-way, and move, or try zooming out a lttle, refocus, then zoom in, refocus, etc - or go to manual focusing. Cameras that use contrast to auto-focus also have trouble in low light- that's why cameras have a "helper" light (orange on s5700) - make sure you're not blocking it! (As with cokin filter system). Go to manual focusing if this doesn't work, but lcd view-finders make this tricky. Another reason for shots being out of focus is you're too close - switch to macro mode if you have to.

When on tripod, and subject is off centre, Neat trick is to look at the auto focus settings on your camera usually only accessible in programme, ap, sp or manual modes - centre, multi, area. With centre - camera looks at the middle of the frame, multi - something near the centre, perfect for subjects that aren't quite in the middle, but the camera chooses!, area - you select where you want the camera to focus. Couple of things to watch out for - depending on camera, although you may focus on something off centre, camera chooses the exposure from centre of image, so go to manual mode to set exposure first. you may find in macro mode the camera will only focus on middle - so go to manual focusing, or lock and turn.

You can also change the amount of sharpening the camera applies to the pictures - but choose it appropriately. Higher is ok for objects with hard edges, buildings, etc, but for most natural objects you'll want to stay with normal.

Post processing. Almost all Photo software has some sort of sharpening tools. Even Picasa and Piknic do - just be cautious. Always apply any sharpening by zooming in to 100% first. In the past I've been guilty of applying too much sharpening, and it does spoil the images - and always keep an original, unsharpened (preferably in a loss-less format, like psd), because the amount of sharpening you require depends on the medium you're going to show the picture. Paper need more sharpening than a computer screen. I tend to use a high-pass filter in Elements or photoshop - technique.

Its good to understand that when you take a picture and your camera saves it as a jpg, its compressing it. and if you edit a photo, save it, then open it again, this process will add noise, artifacts, and you'll lose detail, so always keep your original untouched and work on a copy, and try to save your edits in a loss-less format (psd), and export or save as jpg when you want to send it to web, flickr, etc.

Recommended Podcast: Photography Podcast - Marko Kulik.

Recommended Site: Moose Peterson.

Recommended Flickr photostream: tenesse gator : (add to contacts so you see new shots) specific set.

Recommended Flickr Group: Creative tabletop photography

Flicker group theme assignment: "time" - plus new "technique challenge". Summer, bright skys, difficult to get really nice shots unless golden hour or cloudy - so lets do some "no sky landscapes" - urban, countryside, seascapes, etc. See the "No Sky Landscapes" Thread on Flickr.

Thanks to everyday jones, here I am for intro music, can be found at podsafeaudio.com

Thanks for everyone commenting on the site, and taking part it the forum and adding their pics.

Thanks for listening,

See you on flickr

Cheers, Rob.

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