MicrobeHunter.com Microscopy Forum

My personal results from using the gradient filter are sometimes hit and miss, but I kinda like the look of this Paramecium shot - I had to raise the ISO right up for a faster shutter speed so its a bit noisy - seemed to turn out okay though with some noise-reduction in photoshop. Really glad to have found a source of pondwater containing these guys.

This is a jpeg copy reduced for upload. 40x 0.70 leitz fluotar, on bhtu, canon 1200D,

Great image. Nicely frozen
How high (ISO) did you have to go?

Very nice shot!

thank you GaryB and 75RR.

I would usually raise ISO up to from 800 to 3200 depending on the illumination - 3200 is pretty extreme case though, and for still objects i
normally hover between 100 and 200 iso with shutter at around 1/20 but for moving subjects i try to use 1/125 or thereabouts.

I have a general query about the GUF filter, with it using up so much space under the condenser does this mean the resolution is affected in a similar way to closing the diaphram? in practice would it be better to obscure the least amount of condenser aperture as you can while still achieving the desired effect?
Whats the deal there? (i find things like this difficult to evaluate visually)

Thanks

Aenima,

I like GUF for 4x to 10x objectives, maybe even 20x. For 40x and up, I prefer to use oblique crescent mask. Neither is the same as closing condenser iris.

thanks ZZFFNN

My main concern really is whether the oblique mask, or GUF - because it takes up so much of the underneath of the condenser, whether it reduces resolution or otherwise degrades the image as a result - a bit like closing the diaphrm reduces resolution in favour of contrast - does the GUF do something similar?

I'm wondering whether it might better to obscure less of the condenser with the filter - if it will increase resolution or in some way improve detail etc etc?

Thanks

Bonjour.
Superbe
Cordialement seb

Properly done GUF or oblique mask won't reduce resolution (because light angle does not change); they only increase contrast, which is unlike closing condenser diaphragm (which reduces resolution and increases contrast).

In most transmission brightfield microscopy, we usually don't lack resolution; we need more contrast.

Where to place filter and how much condenser to mask is based on subject and preference.

zzffnn wrote:Properly done GUF or oblique mask won't reduce resolution (because light angle does not change); they only increase contrast, which is unlike closing condenser diaphragm (which reduces resolution and increases contrast).

In most transmission brightfield microscopy, we usually don't lack resolution; we need more contrast.

Where to place filter and how much condenser to mask is based on subject and preference.

oh cool that is a big help - thank you

I find stuff like that difficult to evaluate - often not knowing whether something is better or worse until i process the image in a graphic editor - having some idea what might work in advance helps me to waste less time and effort when testing things out.


The GUF does seem to be a great addition to microscopy and imaging (especially on a budget) - big kudos to the filter's creator.