Lighting

[chapman]

Hi guys, I'm trying to take some pictures of river invertebrates which I've taken back to the house for identification. I've had reasonable success with illumination direct sunlight but wondered if there's a cheap light source that I could use for the cloudy days.

 

Tried using my 500W halogen site light yesterday but was surprised to find it gave the images a yellowish hue

 

 

I use the macro function on a 6mp Sony Cyber Shot for the shots I take.

C

[jeepster]

I'm no expert on still photography, but if you're getting a yellow hue, is there a white balance control on your camera? This could be what you're looking for.

[chapman]

Ah! Thanks Jeepster, there may well be and just as soon as a replacement book of operating instructions arrives from Sony I'll be able to find out. Sounds like a good possibility.....

[Sharkbyte]

Like Jeepster says, have a fiddle with the WB settings.

 

Use 3200k (tungsten illumination) as a starting point, I shouldn't imagine a suitable WB for halogen to be far from there.

 

500 watts sounds pretty harsh. If you can overcome the white balance issues, how about getting a couple of 125 watt halogens for lighting from either side? It should produce far less in the way of shadows and the best thing is, they only cost a fiver or so.

 

Seeing as the 125 watt lamps radiate far less heat, it's possible that you could try correcting gel filters (coloured sheets) that go over your light source, to negate the colour cast your experiencing.

[chapman]

That's very helpful SB, thanks.

Had a tentative dig around in the camera, found WB menu and found five settings which I'd previously ignored, Auto, Daylight, Cloudy, Fluorescent and Incandescent. I guess Incandescent would be the choice for inerior lighting.

 

Had a look atthe ISO settings too (another menu I'd never looked at.....) and did a bit of reasearch on the net to find out what that was about. It appears it has a similar effect as the speed rating of film. With a bright interior lighting set up would I be right in thinking that a setting of 200 would be best for hand held makro shots as regards reducing blurring caused by the camera moving ?

[Westie]

That's very helpful SB, thanks.

Had a tentative dig around in the camera, found WB menu and found five settings which I'd previously ignored, Auto, Daylight, Cloudy, Fluorescent and Incandescent. I guess Incandescent would be the choice for inerior lighting.

 

Had a look atthe ISO settings too (another menu I'd never looked at.....) and did a bit of reasearch on the net to find out what that was about. It appears it has a similar effect as the speed rating of film. With a bright interior lighting set up would I be right in thinking that a setting of 200 would be best for hand held makro shots as regards reducing blurring caused by the camera moving ?

 

Hi chapman. Welcome to the forum. Stick around - it's a friendly place.

 

With ISO, you're right - the same as film speed. The higher the ISO, the grainier the picture becomes, but also the higher the shutter speed you can use to avoid blurring your shot. With macro stuff, movement of any kind will ruin the shot, so if using the camera hand held and in bad light, you'll need to up the shutter speed and ISO will have to go up to compensate, unless you use flash.

 

Usual rule of thumb is to use a shutter speed of the same equivalent as the focal length. If the focal length was 100mm, say, on a DX camera, that would equate to 150mm, due to the 1.5x crop on the sensor. That would usually mean a shutter speed of at least 1/150th second to get a non-blurred shot. That will probably push the ISO well above 200 to enable you to use that shutter speed and expose the picture properly.

 

Likelihood is that your camera will do all of this for you automatically, but if it has a manual mode, you could experiment.

 

Another alternative is to use a tripod, so that you take away motion blur from camera shake. This would allow you to get ISO down to 100, but with a longer shutter speed/exposure time. If you are photographing still subjects, it might be the way to go? You could use the self timer too, to avoid shake from prodding the shutter release. If you don't have a tripod, you might be able to rig something up, to brace the camera.

 

Post up some shots! There's some people here with huge knowledge. I'm still wet behind the ears.

 

Westie.

[Snatcher]

And I am absolutely "dripping" behind the ears Westie!!! :unsure:

[chapman]

Good one Westie, I seem to have got the wrong end of the stick regarding ISO, I'll set it at a higher speed when I take my next kick sample.

 

To give you an idea of the size of the stuff I'm attempting to photograph this 5p piece gives a handy scale -

 

 

 

.....and here are some the invertebrates whose existence and abundance should help to gauge the health of the river over the coming years -

 

Stonefly nymph

 

 

 

Caseless caddis (sedge fly)

 

 

 

Heptageniidae nymph (upwinged fly)

 

 

 

 

Heptageniidae nymph Mk2 (upwinged fly)

 

 

The former shots were taken in daylight with automatic settingsand I considered them to be reasonable, the trouble came using the 500w halogen lighting, hence the query! -

 

Heptageniidae Mk3

 

 

Mating Gammarus, freshwater shrimps

 

 

 

Hog louse

 

 

 

 

As you can see the yellow hue came to the fore despite a bit of editing.

 

The first images were taken in water contained in clear glass with white paper beneath, the second in water contained in white plastic.

 

Now I'm looking forward to the next batch of images taken with the benefit of the advice that I've had from here, thanks all!

Colin

[J.K]

Thats some pretty cool stuff

 

If you are able to change the White balance manually then you should be able to produce something like this. Fixed one of your images

 

 

The auto settings you have found are ok but dont always work correctly.

 

Amazing pictures and cant wait to see more of your pictures !

Edited November 7, 2007 by J.K

[chapman]

Nice fix there JK, many thanks.