Toadstool 3 and Colour Temperature

A toadstool in Murphy's Bush, 
July 2001.

Note the red club fungi in the background. The photographer failed to notice these at the time, but the close-up photography was revealing.

Notice the little hairy white thing? The photographer missed its significance at the time. Probably a piece of pooh. Fungi like growing on dog pooh and dogs love Murphy's bush. The revelations of macro photography...

Stereoscopic images in X and U format. 

If anybody has a name for this toadstool, please reveal it by e-mail: 
or in the  guest book

(Hypheloma species?)

Colour temperature in the forest

Fungi have delicate colours. It is proving difficult to capture them correctly, using natural light photography. Light eventually reaching the forest floor is heavily filtered through the leafy canopy. The sky may be blue, or more usually diffused by clouds, but high temperature colour reaching the forest roof is further changed by the green canopy before reaching the mushrooms. Digitally presetting colour temperature to "shade" has proved inconsistent.

An obvious cure is to use flash, with its guaranteed colour temperature, ease of setting the exposure and lack of motion blur. Flash has been avoided so far, because it "looks unnatural", but that decision is being reviewed!    I dislike ring flash as being very unnatural. Natural light can be emulated with flash by using subtle diffuse lighting from at least two flash heads. The prospect of carrying a portable lighting studio plus a tripod into the bush is not welcome, but probably will happen. All images are from a tripod since macro stereo photography demands considerable precision in setting up the shots. A grab shot with flash is not the answer for quality stereo. The tripod has to have an extension reaching down to the forest floor or across to a cliff face. I use a Manfrotto with bar. On the forest floor a small table tripod (Culman) often works better than the Manfrotto, so I  carry both tripods.

Nikon Digital

• Very recently the author changed to a Nikon 4500 digital camera, which has preset colour temperature, by measuring from a white card. This is a big improvement.

• The additional ability to spot focus and/or spot meter on 5 different areas is useful when setting up pairs of 3D images. 

Even using colour metering, it is still possible to spoil colour by varying the exposure. 

• Nikon are very proud of 256 point matrix metering, but it is a snare in the forest where the background is often very dark and the mushroom much lighter, but to varying degrees. 

• Judging by the histogram (another vital feature of a Nikon 4500), matrix metering is very precise at setting the exposure half way between darkest and lightest objects. The forest is not only dark, it has a huge range of brightness even when direct sunlight fails to get through. Matrix metering ends up failing for both the highlights and the shadows! 

• The shadows are of no interest, so exposure compensation to show the fungi, without blowing out specular reflection from their wet surfaces, is vital. Exposure correction is often -0.7 but may reach -1.7. The histogram function is a big help when adjusting exposure. Spot metering on mushrooms has not been a reliable solution because light reflection from them is so variable. Older pictures were taken with a Nikon 995, which does not have all this sophistication and they show even more incorrect colours than the 4500. 

How did we take forest pictures on film? By using spot exposure metering, manual settings, 81 series filters, reciprocity correction, brains and occasional 3-stops-under white pre-exposure.  Automatic digital everything is getting in the way!

• Nikon digital auto-focus is poor under low light and may fail on a smooth mushroom top, even when the light is good - well... as good as it gets in the forest depths. Canon G series cameras project a red pattern onto low light scenes to allow focus, but Nikon have not provided that feature, which is a major defect. I now carry a piece of crumpled tin-foil to spot focus on. This not only allows Nikon auto-focus to work in dim light, it also dictates just where the camera will focus (which should be half way into the depth of field range for macro work).

• Nikon permits a much bigger reproduction ratio than Canon, without needing a supplementary lens. However, do not be snared into the otherwise most desirable Nikon 5400, because it focuses closest at extreme wide angle, does not magnify as much as the 4500 and has barrel distortion on wide angle, which is hopeless for stereoscopic photography. There are Nikon 5400 pictures on this web site, but not at high magnification. 

• Canon uses infrared remote which is preferable to Nikon's USB wired remote. The USB somehow manages to get slightly unplugged at difficult moments and turns the camera off when re-inserted. Despite its problems, the Nikon remote cord is a major reasons to move from a 995 to a 4500 since camera shake, even on a tripod, is a major hassle in long exposure, macro, stereo-photography.

The background to this page is a good example: it is the same mushroom as the main picture, taken within minutes of each, other but the colour, is quite different. (Both using "shade" colour temperature setting, but slightly different auto-exposure, on a Nikon 995 CoolPix.)

Nikon 4500 versus Nikon 995: more than just more pixels...

Nikon 4500 versus 5400: more than just less pixels and a reduced wide angle range and lack of an on camera flash connection...

Canon G5  versus Nikon 5 megapixels: a hard decision, especially if you already have Nikon accessories...

BUT the Nikon 4500 CoolPix accessory lenses do not go with the 5400 or 5700 CoolPix cameras. CoolPix is not a system - just a cool name!

.Use the middle two pictures for U stereo

 Use Arrow keys to pan right if necessary