petrochemist

There are multiple factors that affect how visible the mesh is. The closer the lens is to the mesh the better The further the subject is from the mesh the better The longer the (actual) focal length the better The wider the aperture the better. With a reasonably long telephoto wide open & touching chicken wire I shot this: The mesh behind the bird is visible but I can't see anything in front. At motorsports there is frequently safety fencing that you can't get close to (or it would provide less protection). Broadly similar settings but around 5 foot from the mesh gave: The mesh doesn't detract too much but it can be seen

I would NEVER go for the best computer money can buy. If you go for one that is merely good (best 2 years ago?) you'll save an absolute fortune, and would be able to upgrade twice as often should you want to (probably not needed). My home computer is actually a 4GB Raspberry Pi 4 which runs a version of Linux & does most of what I need, for under £200 (excluding external drives, but including other peripherals). The 10+ year old laptop I have is now a bit slow but will run any unusual software I want to play with.

No not T-mount, I've heard Hanimex had their own variant adaptable mount. I don't think I've come upon any yet. Perhaps I should double check my Hanimex & Palinar lenses :) FWIW T-mounts are still popular for mounting to telescopes (& to a lesser extent microscopes) but more commonly known as T2 now - I don't think there's any difference in thread or registration officially the T2 allows orientation to be adjusted, but the names seem to be used interchangeably.

Indeed it's what you what you use it for, but it's effect does require the effect to be compensated, or the pond floor will be invisible.

As far as I know there is no such thing as a digital polariser. Newer filters sold for digital may have better coatings but they still polarise light using real light before any digital to analogue conversion. Polarisers themselves can be high extinction or high transmission types, then there is a linear/circular choice depending on if a quarter wave plate is added. It doesn't work well combining two circular polarisers (at least unless you switch one round - two CPLs back to back give very weird effects, front to front they can work like a variable ND). You can get perfectly good results using a 50 year old linear polariser on a digital camera, my grandfathers old 'pile of plates' polariser (probably over 100 years old) would also work if it was a bit wider - less than 1/2" diameter is just too small for my lenses. FWIW circular polarisers came out long before digital photography was practical, yes they work fine with film as that's what they were originally made for! I think my first CPL was brought in the mid 1980's

Usually the effect of the filter is small enough that you don't need to allow for it, but if a significant amount of the incoming light is all polarised in the same direction you may need to compensate if not using TTL metering (self compensating) On occasion I've had reflections from water that provided far more than half of the light. Arrange the polariser one way & expose for the reflection, twist it by 90 degrees & you have to expose for the dim pond floor...

Only if you're using a mirror on a mirrorless :)

There's always macro of items round the house: Watch Macro by Mike Kanssen, on Flickr

I wouldn't call those doughnuts subtle, but the subject is attractive enough to make them bearable! I have taken a few where the bokeh is more distracting, but the vast majority it hardly shows at all.

Reading you first post again I suspect it's actually a 35mm lens designed for 16mm film format. Cine projector lenses frequently have extremely short rear distances and the parts separating could be just a focus mechanism. Removing a group of elements for a lens design often gives another usable lens which typically has uncorrected aberrations - giving rise to your lovely impressionistic results.

Whilst reading your first post I thought it was 16mm format & 35mm focal length, but the two part design does pretty much rule that out. I think formats could easily be the meanings It's very difficult to judge focal length with macro subjects, & projector lenses can have very short rear focal distance (infinity focus probably impossible). Can you estimate the focal length by (unmounted) comparison with other lenses?

A very generous offer Stan. I'd probably find several of them useful, but I'm in the UK so postage would no doubt be significantly higher :(

Oh yes Custom White Balance targets are another one, I tend to forget :)

If I keep secrets it's because I can't remember myself, legacy lenses & filters (I often shot IR so filters are important) can both fall into this category, if I don't note them down quickly.

I've always heard that the longest focal length contax lenses required the Flektoskop, Flektometer or Panflex mounts which add a reflex viewer, effectively turning the rangefinder into a SLR. As well as many printed sources over the years claiming rangefinders were limited to 135mm for focusing reasons (it would take me years to find them) this can be found at Contax rangefinder If this is inaccurate perhaps the Contax, which is often acknowledged as the best rangefinder managed to stretch things somewhat, with really top grade hardware.

In P mode the camera decides aperture & shutter speed to give good exposures according to parameters the manufacturer set.If the light is sufficient to achieve reasonable shutter speeds the aperture will often be closed to increase DOF. Like Joe I don't use P mode, I usually fix the aperture & let the camera sort out shutter speed to match, so I've not become familiar with how my different cameras tend to behave when left to their own devices.

Not just typically, it's one of the features that DEFINES L39. The L denoting Leica and indicating a rangefinder mount with 28mm flange distance. There have also been other M39 rangefinder lenses with slightly shorter flange distances but these were never really popular. Mine was relatively easy to modify so they can be used on L39 bodies/adapters. There are SLR cameras that use the same M39 thread, but with greater flange distance (sometimes called Z39 for Zenit m39), using L39 lenses on these limits you to close-up shooting as the lens will be about 20mm further from the film than it was designed for. One possible partial exception are the retractable 50mm lenses like the Industar 10 - I think these when not extended are close to Zenit m39. Of course when retracted the rear of the lens will foul on any SLR's mirror so they could only be used with extreme care using mirror lock up. Then there have been enlarger lenses using m39 threads too - these have no fixed flange distance. Range finder lenses are not made in focal lengths greater than 135mm, with one of these mounted on a Zenit m39 body the maximum focus distance is about 1.6m, any shorter focal length will focus closer still.

I've picked up several tripods from charity shops but nothing of that quality & very rarely have they been that cheap! The only full size one cheaper than that was probably the last one I got IIRC it was £2 brought for curiosity value as it had a cable release built into the handle.

I find helicoids are much better for this. (I see @mike_halliwell has already suggested them) There are now a wide range sold in M42 mount as well as short M42 adapters to fit them on mirrorless bodies. My shortest helicoid is only 10mm long, and I have others out to 90mm. All my sets of bellows foul on the flash bump of several of my cameras so often need extra extension.

plasma-ball portait by Mike Kanssen, on Flickr

Fresnel by Mike Kanssen, on Flickr or Crystalised light by Mike Kanssen, on Flickr

No so significant but this view from my bedroom window shows a scene sadly no longer visible - the view of the fields being completely blocked by new houses. ultra flashgun by Mike Kanssen, on Flickr I never did work out the guide number of the lightning strike.:)

Full Spectrum rainbow by Mike Kanssen, on Flickr

Taken me a while to get this one on-line but at last here it is: Crystalised light by Mike Kanssen, on Flickr

720nm IR with a 500mm mirror, sorry the subject only has a 70-210 IIRC. Nikon Shooter by Mike Kanssen, on Flickr