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Old January 22nd, 2005, 11:58 PM   #1
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Macro Lens question

I am trying in vain on Ebay to find what everyone is using as a macro lens in front of the camera - but most of them are tubes?!? Am I missing somethings? What should I type in so I get the correct search results for the Macro lens when trying to create the mini35/aldus35?

Thanks
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Old January 23rd, 2005, 01:01 AM   #2
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macro filters seem to be the popular piece of equipment for these devices. 2 10x filters.
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Old January 23rd, 2005, 07:12 AM   #3
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Glossary of terms:-

Macro lens. (attachment) = Close-up lens.
Lens tube. = Hollow tube threaded both ends.
Filter. = Optical device. Screws on front of cam.

Some slight misuse of these terms in describing the products has crept in. Any wiser player out there please correct me if I am beginning to make a fool of myself before damage is done to the knowledge base.

"Macro" as I understand it, is an accessory function which was added into camera lenses. It enabled a lens to focus on close objects whilst the zoom function was at it's narrowest field of view. It provided a "close-up" functionality to the lens and eliminated the need for another piece of glass, a close-up lens to be attached to the front for the close-up shots. Somewhere along the line, separate attachable close-up lenses became known as "macros".

A "Filter" as I understand it, is a piece of glass which is attached to the front of a camera lens or sometimes between it and the image plane to do something to the image without affecting the actual focus. It may be to exclude some colours of light, eg., type 85B to enable daylight filming with film which is balanced for tungsten light, or eg., neutral density filter, to exclude a measured amount of light to enable a slower shutter speed or wider lens aperture to be used, or eg., pro-mist filter, which does affect the image for creative purposes by softening it without necessarily diminishing the clarity of the image too much.

LENS TUBE. As I understand it, is a tube, threaded at both ends or with a male and female mount at each end. It fits between a camera lens and camera body to place that lens furthur away from the image plane. The purpose for doing this is to make that lens capable of focusing on an object closer than it was designed to do, giving it thus a close-up capability.



Okay, now to some descriptions -

Simple single element (= one piece of glass) close-up lenses (or macros as they now get called) are often set inside a metal ring wich screws into the accessory thread on the camera lens. This sometimes gets called the filter thread. Filters, which are usually one piece of glass are also set inside the same sort of metal ring which attaches to - guess what - what has come to be called the filter thread.

So, language evolves and the accessory mount becomes filter mount - the close-up lens becomes a macro lens - by association, the macro lens becomes macro filter, which of course it is not.

Some small camcorders do fine for close-up work without need for an added close-up lens as they have their close-up or "macro" function built in.
So for the AGUS/ALDU, for such a camcorder, the image path should look like :-

subject >> SLR lens >> groundglass >> camcorder.

For the camcorder which has less or no close-up function the image path should look like :-

subject >> SLR lens >> groundglass >> close-up(macro) accessory lens >> camcorder.

The ALDU builders especially desire an even light spread across their entire image because they need to use a larger area of the groundglass to keep the texure of their fixed groundglass fine enough in the overall image that it does not matter. The improvement is valid also for the AGUS builders to seek.

This image path is generally :-

subject >> SLR lens >> groundglass >> condenser >> close-up lens (when used) >> camcorder.

A variation on this is :-

subject >> SLR lens >> condenser >> groundglass >> condenser >> close-up lens (when used) >> camcorder.

Some other visitors here might chime in with names of products :-

The ones I know of are :-

HOYA.

Close-up attachments (single lenses)in three-pack.
Close-up attachments as achromatic diopter.

CENTURY OPTICS.

Close-up attachments as achromatic diopter.


If you are serious about image quality, the single lens close-up attachments are not recommended.


In the ALDU application, lens tubes are being used as a very precise and stable means to hold a groundglass and the SLR lens on the front of a camcorder. Some developer-builders are using stacks of empty filter rings to make adjustable lens tubes in effect.

Hope this helps and is not too pedantic.
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Old January 23rd, 2005, 08:43 AM   #4
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No, that helps alot! But definitely leads to new confusion as well in this quest.
I kept wondering why (and this is my lack of knowledge) people weren't trying to find a way to put a SLR lens in front of the camera and leave it at that? Therefore is you figured out how to do that, you could use all the 35mm lens you wanted! So after thinking about this, I guessed it was one of two things :
1) there was no way to properly attach it
2) there was no grain, therefore people started using the groundglass.

I was thinking of creating a double female ended PVC attachment that would hold the 35mm lenses to my DV camera :

35mm lenses/groundglass << female end PVC PIPE female end << DV camera

Wouldn't this be a much easier solution? Couldn't one, therefore use step-up rings to attach the ground glass to the 35mm lenses, or anywhere in between?
To me, this would eliminate the spinning CD.

But thinking about this further, my MiniDV has a 44mm threaded front, so wouldn't I really just need is to find step up and down rings to attach to a macro lens, ground glass and then small section of PVC pipe attachment and then the 35mm lenses in front?

Somebody please correct me if I am thinking about this the wrong way!
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Old January 23rd, 2005, 10:46 AM   #5
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What we need on this site is a tutorial on the basic theory of these adapters :D. Maybe I'll write something up sometime and post a link.

Mandy,

The reason for the ground glass is more complex. The ground glass acts as a projection screen that captures the image from the 35mm lens. This allows us to retain all the properties of the 35mm format. It's like projecting a movie on your wall and then filming it with a video camera. Same basic idea.

If we didn't have the ground glass the camera would only pick up a very small piece of the 35mm frame which causes all sorts of trouble with focal length, depth of field etc. Basically you can't just attach a lens to the camera. It doesn't work. Partially because the image plane of the 35mm lens does not line up with the cameras CCD. Everything would be out of focus.

Hope that was some help.

For your purposes I doubt you will need a macro lens since your camera has a 44mm thread. The macro comes into play with larger cameras such as the XL2 and DVX which have 72mm threads.
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Old January 23rd, 2005, 10:51 AM   #6
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Oh, ok. I think it is 44 or 43. I have an adapter for it because I purchased a Tele and Wide angle lens a while ago for it.
So, back to your point - you say I don't need the Macro lens - but when I use the Tele lens I have for me camera, I still get Tunnel Vision when I use it if I focus with too wide of a shot (I know Tele is for bringing things in closer, so I really wouldn't need a wide shot with it on anyways). But that is why I wondered if a Macro might be needed :

I am using the PV - DV852 from Panasonic. It is a great little camera and I am realy trying to figure this out and then build it. Learning is fun in this case and it really makes me appreciate photography and those that understand it alot more!

So my next step it to build a mock up of it.

PS - why do the GL2 and the DVX need the macro lens?
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Old January 23rd, 2005, 11:38 AM   #7
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Mandy, can you post a picture of your setup? It would help me understand how to help best.
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Old January 23rd, 2005, 02:41 PM   #8
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<<<-- Originally posted by Mandy Leo :
PS - why do the GL2 and the DVX need the macro lens? -->>>

They use filters. Personally I don't know, I guess because of the large sized default lens.
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Old January 23rd, 2005, 05:12 PM   #9
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So is the groundglass like the FILM STOCK in a 35mm camera? it takes the image? If this is true, then I can understand that. Right now, I am just trying to make a mock up of it and see what happens.

Here is what I think it is supposed to look like : corrections would be great - and this is without the housing (of coursE)

http://dvstuff.250free.com
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Old January 23rd, 2005, 05:34 PM   #10
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Yep that looks about right. You will need to experiment to find the right amount of spacing between the ground glass and macro and between the ground glass and 35mm lens.

Yes the ground glass acts precisely like and takes the place of the 35mm film.
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Old January 23rd, 2005, 05:45 PM   #11
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Have people tried using the TELECINE machines ? I have one that I used to use for converting 8mm/16mm to video. Basically, project through one end, at a 90 angle and mirror ,stick the video camera in the other end and record.
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Old January 23rd, 2005, 07:37 PM   #12
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Ok, I did a mock up test : had my video camera in front of the GG and then my MACRO KIRON lens on the other side - but nothing happened. I could barely see what was through the lens of the KIRON, so maybe I have the wrong kind of 35mm to use for this? Anyone spot the obvious error I am making?
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Old January 23rd, 2005, 09:56 PM   #13
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In an earlier development to relay night-vision, I tried the two lenses out of a Sony VCR16 which are a module which faces the projector and screws into the mirror case. I did not use the mirror, just the lens pair after taking out the ND filter.

This performed as a close-up lens to about 7+ power and was distortion-free onto a 2/3" target. How it would go with a standard movie frame of 24mm x 18mm I didn't test for.

Looking at your camcorder from the left side this is what your order of assembly should be starting from the left (= front-end ) and going back to the camcorder.

subject >> SLR lens >> groundglass >> Kiron Macro >> camcorder.

I'm only guessing here but to use your wide-angle as a close-up lens or macro, if it is constructed in two parts to enable close-up work, you may first have to remove the front element and just use the rear half which may even have "macro" written in red letters on it. Some are made in two halves to work like this.
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Old January 23rd, 2005, 09:59 PM   #14
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The only problem is that the Macro lens is a huge tube! About 6inches long! And with an SLR end, I can't connect it to my DV camera. I might have to buy a Macro lens that will fit my miniDV and then continue to look for a 35mm lens for the front.
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Old January 23rd, 2005, 10:09 PM   #15
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Mandy.

Ignore anything in the previous post which refers to the Kiron lens. By your description I assumed it was a close-up attachment for your camcorder but in your other post it is described in more detail and seems to be maybe, a zoom lens for a still-camera which has a "macro" (Close-up) function built in.

What sort of mount does it have on the back? If it is a "one fits all" type then it may be an older "T Mount" which was a universal mount which enabled third party lenses to be fitted to particular cameras via adaptors.

For useful help, you might need to describe your various lenses and pieces by including the details printed on the lens body, model numbers and the print on the ring around the front piece of glass in the lenses and also on front of your videocam lens itself.
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