Hall Sensor and magnet and trigger

[MattiasN]

I want only show how i did get the hall sensor to work maby it help´s someone

here are two photos

picture one it´s the same photo that is on Frank´s homepage i did copy it from there but i did edit it little





picture two it did look like that when i did test how the hall sensor works

[carllooper]

Nice

[MattiasN]

Thanks

[MattiasN]

i did fix some more photos about trigger and hall sensor






and i did take some photos of my new camera mount

http://www.flickr.com/photos/94271811@N03/

[carllooper]

Thanks Mattias.

The Super8 captures you are getting there are really quite extraordinary. Extremely inspiring. Would love to see any motion tests you might be trying.

C

[MattiasN]

Thanks

heh did try to google about motion tests but i do not get what you mean

heh i did test on my printer scanner and see how good it does the super 8mm test film here is a photo of it and it was scanned with 5600 dpi if i remember right

http://www.flickr.com/photos/94271811@N03/11315937865/

hmm the focus are off i gess maby if the glass on the scanner gets a tiny adjustments maby i get beter focus or maby this is the best it can do

[carllooper]

Thanks

heh did try to google about motion tests but i do not get what you mean

heh i did test on my printer scanner and see how good it does the super 8mm test film here is a photo of it and it was scanned with 5600 dpi if i remember right

http://www.flickr.com/photos/94271811@N03/11315937865/

hmm the focus are off i gess maby if the glass on the scanner gets a tiny adjustments maby i get beter focus or maby this is the best it can do

My apologies. What I really should have said is "moving pictures", ie. as distinct from still frames.

Carl

[MattiasN]

Ok

heh i did buy two more lens from ebay again have to test more what is the best lens

it was RODENSTOCK APO RODAGON N 2,8/50mm and Leica Leitz Focotar-2 1:4.5/50

but i have a feeling that the lens i have allready is the best maby Rodenstock APO-RODAGON D 75mm 1x f/4

[carllooper]

Ok

heh i did buy two more lens from ebay again have to test more what is the best lens

it was RODENSTOCK APO RODAGON N 2,8/50mm and Leica Leitz Focotar-2 1:4.5/50

but i have a feeling that the lens i have allready is the best maby Rodenstock APO-RODAGON D 75mm 1x f/4

Just checking my lens - the one I'm using here is actually the same as the new one you've acquired (rather than the previous one): it's a Rodenstock Apo-Rodagon N 1:2,8 f=50mm

Be sure to post any comparisons you make.

C

[MattiasN]

Yes of course

if i have understand correct when i have 1/1.8 sensor size on the camera it´s about the same size as super 8 maby little bigger but it´s close to 1:1 and becuse Rodenstock APO-RODAGON D 75mm 1x f/4 is optimized to 1:1 then i have the feeling it´s the best of the lens i have or maby not but in the future maby i buy bigger sensor size camera then it´s not going to be near 1:1

and here is a comparisons Rodenstock APO-RODAGON D 75mm 1x f/4 and it´s close to the Printing Nikkor 2,8/105 mm in some areas

http://www.photomacrography.net/forum/v ... p?p=106347

[carllooper]

It's not optimised for 1:1 or any other magnification for that matter.

The original application of the Rodenstock lens is for a photographic enlarger, ie. where you would blow up (enlarge, magnify) a photographic negative (film) up to whatever size of photographic paper you wanted to use, which could very well be 1:1 but typically (much more often) not.

When we call a 1:1 magnification "normal" we are really just defining what the word "normal" means (it means a 1:1 ratio), rather than describing the ratio. It's a reference ratio. It's a way to make the mathematics easier to do. One speaks of "normalising" the magnification, which is to say: to assume a 1:1 magnification. By doing this we can then alter the normalised magnification in some equation to obtain what other magnifications would otherwise give us. The designation of 50mm as the focal length (on the lens I have) is also a "normalised" focal length. It is what the focal length would be if the lens was focused at infinity. This does not mean the lens is optimised for 50mm (or focus at infinity). It is just a reference value. It is from such a reference value we can then vary the focal length (away from 50mm) and work out where the focus would be for other focal lengths.

In a film transfer setup we are just replacing the photographic paper with a photographic sensor. Using the lens is not unlike using the lens of a Super8 projector, except we're projecting the film onto a sensor instead of a wall. And like a projector we would move the projector (film/lens) back and forth with respect to the wall in order to vary the size of the image on the wall (or on the sensor). Or move the wall! And we would vary the film to lens distance to adjust focus. However they are inter-dependant, ie. changing focus also changes the magnification by a certain amount and vice versa, so it makes it a little tricky. You can't just lock off one distance and vary the other. You have to vary both distances by different amounts to get (or maintain) a particular magnification and/or focus. Typically, of course, the only focus we are interested in is the one which produces an "in focus" image.

So you vary the lens-to-film distance, as much as the lens-to-paper (or lens-to-sensor) distance, to find the specific magnification and focus you are after. Now there will be mathematical equations involving the lens focal length and film/sensor sizes that would determine exact distances to use in order to obtain a particular magnification/focus result, but eyeballing trial-and-error results on a suitably adjustable rack (as you are doing, and I'm also doing) is the conventional method. It is a what-you-see-is-what-you-get (WYSIWYG) methodology.

The maths comes in useful when you want to design a setup without having to go through such a trial-and-error process. Of course, if you make a mistake in your maths (which is easy to do) you won't see it. The benefit of making a "mistake" in reality is that it's both visible and not actually a mistake!

The main benefit of an APO lens (and similar lens) is not any particular magnification for which they would be designed, but that they correct for chromatic and spherical aberration - which is just that all the more important when working at the very small scales we are working.

http://en.wikipedia.org/wiki/Apochromat

C

[MattiasN]

Thank you for the info and for clarify that to me

heh i burn much money on lens i did pay this for

Rodenstock APO-RODAGON D f=75mm 1:4,0...................181 euro
Rodenstock APO RODAGON N 2,8/50mm........................270 euro
Leica Leitz Focotar-2 1:4.5/50....................................121 euro
SCHNEIDER KREUZNACH OPTIC Componon-s f/ 2.8 50mm....59 euro
LINOS MeVis-C 50mm................................................312 euro
TECHSPEC® Compact Fixed Focal Length lenses 35mm......280 euro

[JhnZ33]

What did you use for a magnet and is it possible to post a photo of the mounting of the magnet and sensor?

[MattiasN]

Hi sure

here i did find tiny magnets http://www.ebay.co.uk/bhp/tiny-magnets

the magnet i did have was bigger but i did cut it with this


i did glue it with this to the wheel inside the projector


here you see the magnet glued on the wheel inside the projector


and here is the hall sensor and magnet mounted


closeup of the hall sensor and the mount

[JhnZ33]

Thanks for the information and pics Mattias, it is much appreciated.