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My new toy
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soldevilla



Joined: 16 Dec 2010
Posts: 550
Location: Barcelona, more or less

PostPosted: Sun Mar 13, 2011 10:51 am    Post subject: My new toy Reply with quote

Because not all will be asking for information I now show the new toy that I have built.
The gadchet is a box that has a flip mirror. I I can bend light to an eyepiece or to pass directly into the chip. It is very useful for centering small frames (I sometimes work with frames less than 1 mm.) and visual image quality is very good. I've even made ​​an adapter to put a binocular head but I prefer to evaluate the image to photograph with one eye, binocular vision is deceptive to photograph.



And one of the first images, an eritrine. Korean 10x objetive

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elf



Joined: 18 Nov 2007
Posts: 1375

PostPosted: Mon Mar 14, 2011 6:32 pm    Post subject: Reply with quote

It looks nice and the results are certainly excellent, but I have to ask why do you need to view in an eyepiece? Doesn't the camera have LiveView?
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soldevilla



Joined: 16 Dec 2010
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Location: Barcelona, more or less

PostPosted: Tue Mar 15, 2011 3:19 am    Post subject: Reply with quote

nop! my cameras are an old 350D and 20D
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SONYNUT



Joined: 22 Jan 2011
Posts: 635
Location: Minnesota USA

PostPosted: Tue Mar 15, 2011 4:47 am    Post subject: Reply with quote

angle finder?
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soldevilla



Joined: 16 Dec 2010
Posts: 550
Location: Barcelona, more or less

PostPosted: Tue Mar 15, 2011 6:51 am    Post subject: Reply with quote

Yes, but no a beam splitter or prisms, only a flip mirror. When I turn the handweel, the way between the objective and the sensor become clean. And when the mirror is in usage, the visual quality is very good. With the binocular head attached I have a fantastic binocular until 200x, better that a commercial binocular.
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enricosavazzi



Joined: 21 Nov 2009
Posts: 1181
Location: Valdemarsvik, Sweden

PostPosted: Tue Mar 15, 2011 8:23 am    Post subject: Reply with quote

SONYNUT wrote:
angle finder?

The big advantage of these optical systems is that they are placed before the camera, and that the eyepiece focuses on an aerial image instead of a ground glass (= much brighter and more detail visible). Precision focusing becomes much easier than on a ground glass screen (as long as the eyepiece has a properly calibrated focusing reticle). I built similar systems with variously modified/unmodified microscope trinocular heads (working on my fourth one now).

When I am able to choose between live view and a properly calibrated trinocular head, I almost always find the latter preferable. But of course, I would not take a heavy trinocular head + microscope body + stand to the field or on a long trip by air.
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SONYNUT



Joined: 22 Jan 2011
Posts: 635
Location: Minnesota USA

PostPosted: Tue Mar 15, 2011 8:44 am    Post subject: Reply with quote

there is no ground glass in an angle finder..you see what the camera sees.
I use a flip mirror for my telescope..but only because i use a block sensor..

calibration is critical....though not for the above rig since he's stacking
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Chris S.
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Joined: 05 Apr 2009
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Location: Ohio, USA

PostPosted: Tue Mar 15, 2011 10:36 pm    Post subject: Reply with quote

enricosavazzi wrote:
The big advantage of these optical systems is that they are placed before the camera, and that the eyepiece focuses on an aerial image instead of a ground glass (= much brighter and more detail visible). Precision focusing becomes much easier than on a ground glass screen (as long as the eyepiece has a properly calibrated focusing reticle). I built similar systems with variously modified/unmodified microscope trinocular heads (working on my fourth one now).

When I am able to choose between live view and a properly calibrated trinocular head, I almost always find the latter preferable. . . .

Soldevilla and Enrico,

You have both picqued my curiousity. I much prefer looking through a right-angle viewfinder to using live view, and your approaches might improve this direct viewing approach. Soldevilla, would you mind adding more details about your "new toy"? Enrico, would you mind elaborating on your first-through-fourth iterations? I'm not sure what a "properly calibrated focusing reticle" is. Forgive me if this is obvious to a microscopist--I am not one.

Thanks! Soldevilla, great "new toy"--perhaps it will become a "great new tool" for people like me.

Cheers,

--Chris
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elf



Joined: 18 Nov 2007
Posts: 1375

PostPosted: Tue Mar 15, 2011 11:29 pm    Post subject: Reply with quote

Now if you can just figure out a way to add a light to illuminate the subject through the lens ...
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Pau
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Joined: 20 Jan 2010
Posts: 4794
Location: Valencia, Spain

PostPosted: Wed Mar 16, 2011 3:38 am    Post subject: Reply with quote

SONYNUT wrote:
there is no ground glass in an angle finder..you see what the camera sees.

There is a ground glass: the camera focusing screen

Chris S. wrote:
I'm not sure what a "properly calibrated focusing reticle" is. Forgive me if this is obvious to a microscopist--I am not one.

This kind of device was very usual in camera microscope adapters some time ago, in special to use with microscope cameras without optical wiewfinder, for exemple:
http://www.alanwood.net/downloads/olympus-photomicrographic-systems.pdf
http://microscope.database.free.fr/540_files/54-3b%20Micro%20Camera%20attachments.pdf
The Soldevilla's approach has the advantage for use direct projection that it don't use an eyepice to form the image like in a classic microscope setup.
An eyepiece reticle is a transparent glass with some engravings (to frame or to do measurements) placed in the same plane inside the eyepiece where the objective image is formed. It would be very conveniet but not necessary.
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soldevilla



Joined: 16 Dec 2010
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Location: Barcelona, more or less

PostPosted: Wed Mar 16, 2011 8:16 am    Post subject: Reply with quote

Hello.

Pau, is not the same thing. Adapters that you show (The Leica PDF shows a section) are two sets of lenses to extend the optical path and a prism beam splitter to split light, a fraction of which goes to the movie and another fraction to the Eyepiece .
My system is much simpler: just an empty tube and a mirror that I can add or remove. I add a picture. A male thread up to attach the Canon adapter, a female thread bottom for attach the objective and a swing mirror into the tube to divert or not the path of light. All the light to the camera or to the eyepiece.

Elf, illuminate through the lens of the objective requires a beam splitter. Do not use a glass plate because it is very possible that it produce a double image. Two prisms glued to their hypotenuse with some oil certainly works, and if not, our usual sources of optical material certainly always have a beam splitter for very little money.
http://www.surplusshed.com/pages/item/l2047d.html

I do not use it to focus, though the aerial image focused by the Eyepiece has a position very precise but also to control the framing and lighting. The accuracy of the focus is the work of the stacking



PD. some astronomical brands have flip mirrors like mine. You can search in Meade, Vixen...
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Pau
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Joined: 20 Jan 2010
Posts: 4794
Location: Valencia, Spain

PostPosted: Wed Mar 16, 2011 9:22 am    Post subject: Reply with quote

soldevilla wrote:
Hello.

Pau, is not the same thing. Adapters that you show (The Leica PDF shows a section) are two sets of lenses to extend the optical path and a prism beam splitter to split light, a fraction of which goes to the movie and another fraction to the Eyepiece .
My system is much simpler: ...


Yes, I agree, those microscope adapters are more complex, for exemple the Leitz Mikas has a 0.3X relay lens and a built in shutter and needs an eyepiece, I have it (old and out of service) and the prism can be pulled out of the optical path.
But the principle is the same: to form the objective image (alternatively o simultaneosly) in the camera sensor or film and in the eyepiece. In both devices the key is the parfocality of the eyepiece and the sensor. Again, in a microscope, the use of a parfocalized trinocular head is based in the same principle.
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g4lab



Joined: 23 May 2008
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PostPosted: Wed Mar 16, 2011 1:27 pm    Post subject: Reply with quote

Usually the only time you want to use a beam splitter type trinocular or photo adapter is when you are observing and photographing live, moving objects and you wish to be able to snap the shutter when it is looking up at you defiantly. Otherwise they waste light with, for example 50% of the light going to the camera and 50% to the eyepieces, at all times.

One with a sliding prism or mirror that can send 100% of the light in either direction is preferable IMO. Of course the venerable Wild M400 could send 100% to the oculars, 100% to the camera, or a 50% split all at the turn of a knob. There have been similar trinocs for compound scopes made but they are usually the most expensive ones.
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enricosavazzi



Joined: 21 Nov 2009
Posts: 1181
Location: Valdemarsvik, Sweden

PostPosted: Wed Mar 16, 2011 1:37 pm    Post subject: Reply with quote

Some of the relevant answers have already been dealt with in this thread. The main points of using a trinocular head (or a beam splitter/prism/mirror box like Soldevilla's, which is also commonly used in photomicroscopy) are three:

1 - The external eyepiece must be perfectly parfocal with the camera sensor.

2 - There is no ground glass in the optical path to the external eyepiece. This means that the image is much brighter than in the camera's viewfinder. In the past, high-end SLRs could swap the ground glass focusing screen for a transparent one, for the same reason, for use in microscopy and astronomy.

3 - With a transparent focusing screen, or no focusing reticle, the eye may inadvertently focus on an an aerial image that is not exactly in focus on the plane of the screen. As a result, the picture will be somewhat out of focus. This is prevented by using a focusing reticle (in the external eyepiece, or on the transparent focusing screen in the camera's eyepiece). There are two correct ways to use a focusing reticle. The most straightforward is to make sure that the image of the subject and the reticle are both simultaneously in focus, without requiring refocusing of the eye. There is a second, more sensitive and slower method, which can be found in microscopy books and microscope manuals (hint: the parallax method).

Using a trinocular head is much like using a beam splitter/prism/mirror box with a single eyepiece. Basically, I modified all of mine by shortening the photo tube and projecting the (normally aerial) image produced by the objective onto the camera sensor - there is nothing more to it (assuming that the image circle is wide enough). A limitation of most microscope trinocular heads is that the field of view in the eyepieces is smaller than the sensor area, so focusing must be done with the eyepieces, but precision framing with the camera viewfinder. Soldevilla's solution uses a 2" astronomical eyepiece (I believe) to overcome this limitation.

If anyone is interested in more detail, here comes the sales pitch (forum administrators: feel free to delete this part if it violates forum policies):

This subject is discussed quite in detail in my book (http://www.lulu.com/spotlight/enricosavazzi). Unfortunately, this part is not available in the partial book preview available at the above link, and the more extensive book preview on Google Books is not online yet (and I have no way to know if it will include the relevant parts - the choice is up to Google). The few (and, hopefully, happy) owners of a copy of this book may look mainly at pages 394-412.

If you don't know anyone nearby who already owns this book, a good way to avoid buying a personal copy is to locate a public or university library that already has one, or to convince a library to buy it. Most libraries have a running budget for book purchases, and usually do accept purchase suggestions from their visitors/members.
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DQE



Joined: 08 Jul 2008
Posts: 1653
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PostPosted: Wed Mar 16, 2011 1:57 pm    Post subject: Reply with quote

<excerpt>:

This subject is discussed quite in detail in my book (http://www.lulu.com/spotlight/enricosavazzi). Unfortunately, this part is not available in the partial book preview available at the above link, and the more extensive book preview on Google Books is not online yet (and I have no way to know if it will include the relevant parts - the choice is up to Google). The few (and, hopefully, happy) owners of a copy of this book may look mainly at pages 394-412.

If you don't know anyone nearby who already owns this book, a good way to avoid buying a personal copy is to locate a public or university library that already has one, or to convince a library to buy it. Most libraries have a running budget for book purchases, and usually do accept purchase suggestions from their visitors/members.

------------------

Is there any chance that this book will become available through Kindle e-books or some other e-book format? I have to admit that I've become somewhat addicted to e-books. I clicked the link on the Amazon.com listing for your book that says "tell the publisher that I'd like to buy this book via Kindle." I'm guessing that Amazon charges a lot of money to digitize and sell e-books...not so helpful for specialized technical books.
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