mike_cowan1

Geoff, thanks very much for the references. They all show the 486nm line as much bluer than it appears to the eye, so apparently I'm not alone in this. In Photoshop I had to select the three lines individually and use 'Hue and Saturation' different amounts with each one to make an image that looked roughly like what I saw. OK for hydrogen, but way too much trouble for a complicated spectrum! Thanks again.

Ellis, I'm shooting both NEF's and JPEG's, and they're identical in colour.

 

Robert, this was a hydrogen discharge lamp, with wavelengths fixed by the physics of hydrogen. In any case, I tried it maybe 20 times under different conditions, and it was always the same.

For a demo/lecture on light and colour, I wanted to photograph a hydrogen spectrum using a narrow hydrogen lamp,

a slit, and a grating. The resulting spectrum was very clear by eye - the central pink line of the lamp itself,

one deep red line, one green line and one deep violet line. When photographed with a D300, the image was the

same central pink line, but the red line was nearly orange, the green line was a light clear blue, and the violet

line was blue with a violet tinge. No amount of white-balance, exposure or ISO shifting could turn the green

line (admittedly a blue-ish green, but still clearly green) into any colour but nice bright blue. A design

problem in the colour sensors? A problem with the extremely narrow wavelength range of the spectral lines

themselves? A flaw in the camera's colour processing? I'd be grateful for any suggestions you have.<div></div>

Thanks both of you for the advice. When I tried the Open with Photoshop route, my version of Photoshop Elements (first?) wouldn't open the nef files. Do you know what's the simplest (= cheapest) version of Photoshop that will?

Have recently purchased Nikon Capture 4.3 and I really like the idea

of maintaining the original .nef image and still having fine control

over white balance, contrast, etc. But for further local

control/retouching, will any versions of Photoshop accept the nef

files as adjusted in Capture 4.3 and allow further processing? If so,

which versions? Are there problems inherent in this process? Thanks

for any information or references.

Having trouble printing a clear bright yellow with Canon S600 on

glossy photo paper. Sunlit autumn leaves were yellow with just a hint

of orange in reality, looked about the same on my monitor, printed a

dull heavy orange. No amount of photoshop manipulation of the file

(saturating and lightening the yellow, practically eliminating the red

altogether)can make the colour print properly. Other colours seem OK

(some difference between monitor and print, but not this extreme)

Anyone else have this problem? (I notice that the 'yellow' 3e ink

cartridges are quite 'orangey' - Surely there isn't a flaw in the

design of such a popular printer ink ??) Grateful for any information.

Mike Cowan

Have been having fun using Photomerge in Photoshop Elements (came with the Fuji S2 camera) to stitch up to 11(!)6MP photos together. You have to reduce the files to 50% or the requirements for computer memory become extreme. As stated, blue skies sometimes need to be smudged a bit at the joins, but otherwise the program works brilliantly, snapping adjacent photos together perfectly. So far, it seems to work best for me with distant scenes and moderate telephotos, to eliminate perspective problems.<div></div>

If you haven't already bought anything, consider a Fuji S2Pro, which I have used for a year, and really like. The controls are intuitive and lie very comfortably in the hand (much more so for my hand than the D100) and it takes Nikon D and G lenses.

Took my M6TTL with the hard metal eyepiece frame (which is scratching my glasses) back to the dealer. Compared mine with three different used M6's: four different thicknesses of rubber ranging from effectively none (mine) to barely perceptible (rubberlike surface but no give to it at all) to thin but usable, to soft and almost cushy. You could see the difference in the overall thickness of the frames. Am sending new camera back to have eyepiece replaced with a proper one. Seems the layer of rubber varies a lot from unit to unit.

Sorry for confusion about the shape of the metal frame - I must have

been asleep. The frame itself is circular - of course it's the

aperture inside the glass that is rectangular. This is a brand new

M6-TTL (elegant box, warranty card, no marks on it, reputable

dealer)serial number 2723655 and the viewfinder frame is indubitably

black anodized metal - protrudes about 2 mm from the back of the

camera. Another example of Leica whimsicality?

My camera store let me try out a couple of different used M6's (.85, .72 non-TTL) while waiting for my new .72 TTL to arrive. The new one has a slightly protruding rectangular metal frame around the viewfinder which scratches my glasses. The used ones had a softer (rubber?) frame. Anyone know if the frame is replaceable, or if there is a standard rubber attachment one can add ? Easily ? I tried rubber O-rings from a plumbing supply, but they were too thin to help.

I don't understand how the camera (the box which separates the lens from the film) could make such a difference. Same film? Same lens? Same exposure? Is the difference consistent? Light leaks? Film flatness? Light scattering inside the camera? There has to be a reason.

Have used old Nikon 200mm f/4 as prime lens(attached to camera via a PN-11 extension, so as to have the tripod closer to the balance point) and 105 mm f/2.8 used wide open as close-up lens (reversed and attached to 200mm via filter thread adapter) Gives a very sharp bright 2:1 image, easy to focus visually, and lots of room between lens and object for lighting. Depth of field is minimal, even with the 200mm set to f/16 or f/22, and vibration is a major problem, both because of the length and weight of the lenses, and because of the magnification. Mirror lock-up is a MUST, but you have to be careful not to move the camera while you're locking up the mirror, otherwise the focus can shift. I found even shifting my weight on the wooden floor beside the camera/focussing rail/tripod between focussing and taking the picture caused unacceptable focus shifts. When it worked it was great, but I learned to take several shots of every set-up, to ensure that at least one was free of vibration and of shifts in focus. The problems are even worse with the 4:1 magnification you get with a 50mm lens in front. For less than 2:1, I'd use a macro lens and extension as needed.

Anyone out there familiar with the Leitz 560mm f/6.8 long focus lens ?

Just bought one (used, on an Internet auction) for bird photography,

attracted by the quick manual focussing, like the 400mm Telyt I

already had. It is, as expected, a very long, rather front-heavy

monster. The sliding focussing action allows nearly zero transverse

play, but is rather stiff. I'd trade a little play for a little less

stiffness. (My much older 400 mm f/6.8 is smooth as silk; it's also a

lot shorter and lighter, therefore much less torque on the focussing

mount.) Will it wear in with use ? Is an adjustment called for ? A

repair ? Or is it just the nature of the beast ? Grateful for any info

from past or present users.

Does anyone have any experience using an old Pentax K-mount SMC 400mm f/5.6 manual diaphragm lens ? Sheer optical quality wide open is what I'm mainly interested in: sharpness, contrast,and freedom from flare. How would it compare to the corresponding lenses by Sigma (which I tried but didn't like) or Tokina ? I'm hoping to adapt it to a Novoflex Follow-Focus bellows for use on largish birds and animals, so its ergonomics don't matter to me. Thanks for any information.