Achromat for HVX200? at DVinfo.net

Lau Ho Ming · December 16th, 2006, 03:01 AM

I know that my school has 2 Panasonic HVX200. But they don't officially offer to students for projects in ordinary circumstance. So I may tell them about my 35mm adapter and hope that they are interested with what I have done.
So I will get a 58mm achromat for PD170 (Which is readily available for use). But is it too small for the HVX? What will happen if I use step-down rings.Notice that I'm a really poor student and can't even afford an large achromat e.g. 77mm, not to mention a camera.

Bob Hart · December 16th, 2006, 03:58 AM

I have tested a 7+ Century Optics achromatic dioptre with 58mm filter thread mount on an older Panasonic DVX100 with a home made 58mm to 72mm step-up ring. This I used with my own flip adaptor for 24mm x 18mm 4:3 frame and it worked okay into the DVX100.

I don't know what the lens on the HVX200 is.

What matters is how wide the front glass on the HVX is. The filter mounts are wider so no vignette gets into the image when the zoom lens on wide.

If the HVX200 lens can zoom in at least to 54mm and if the HVX200 uses a 1/3" CCD, a 58mm 7+ achromatic dioptre has a chance of working. I don't know about a 4+. The 4+ does work on a Sony FX1 with lens zoom all the way in to 54mm for 24mm wide groundglass image.

The adaptor has to be very long about 200mm for a 4+ dioptre onto a 24mm wide groundglass image.

All the clips posted by agus35monk at YouTube have vision shot with a +7 dioptre used on a PD150 or FX1 type camera.

The "b-movie heroes" clip has Letus35 footage as the close-up roving cam. Only the very first image of the microphone is Agus35 image in that clip.

Lau Ho Ming · December 23rd, 2006, 04:27 PM

The HVX200 has 82mm(It's huge...) filter mount.
If I use have to step it down from 82 to 58 mm. Will it cause vignette with proper zoom through?

Bob Hart · December 23rd, 2006, 07:52 PM

If you can get hold of the HVX200 for a few minutes test you can try something.

Find a piece of thin cardboard. Cereal or biscuit packet is okay.

Cut out a circle 82mm diameter on outside and 48mm inside diameter. 48mm is the internal diameter of the rear optical path of the +7 Century lens. To this circular piece of cardboard I will now give a name "cardboard pattern"

Support the cardboard pattern across the front of the filter mount with tape, not inside the filter mount. If the cardboard pattern goes inside the filter mount, it will be closer to the camcorder lens and will spoil this test.

If the camera has an underscan viewfinder, power the camera up and select underscan on the viewfinder. If it does not have an underscan viewfinder, you will have to find an underscan monitor and connect the camera to it.

When the camera is running, adjust the zoom lens to wide. You will see the vignette the cardboard pattern will cause.

Slowly zoom in. If the vignette is outside of the frame by zoom position 32mm, the +7 is likely to work on this camera for a frame wider than 24mm on the groundglass.

A wide frame is going to give you problems with hot spot (corner brightness fall-off). If you want to use a wide frame, you will need to use condensor lenses to fix this problem.

If your camera zoom can go to 54mm or higher number, you should be able to zoom closer on the groundglass to a smaller image, 24mm or slightly smaller. If you are happy to use a smaller groundglass area, this will fix the hotspot problem.

If your camera can pass this test, borrow or buy a cheap 58mm mount Hoya close-up lens set for another test. Barcode number for this is

" 0 24066 58021 4 "

The Hoya kit contains three lenses, +1; +2; +4.

These stacked together will give you +7 for testing. The image will be not good for production but good enough for this test. You will need another person to help you with this test.

Draw a 24mm x 18mm target on a paper or cardboardwith thick felt tip marker pen. Draw this target with cross lines to make a grid. Don't make it all one colour because you need the lines to see if there is sharp focus or not.

Screw all the lenses together. The +1 should be closest to camera, next is +2 then +4.

Fit the camera on a tripod. Set the camera lens focus on about 1.8 metres.

Place the target about 150mm from front of camcorder lens. The centre of the target must be exactly aligned with centre axis of camera lens.

Fit your cardboard pattern in back of the Hoya lens stack.

Hand hold the Hoya lens stack and offer this up to the camera using the cardboard pattern to make the position centred correctly.

In the camera viewfinder or monitor, your should see your 24mm x 18mm target. Ask your assistant to adjust focus and zoom until your target comes in close enough to fill the frame side to side and is clear and sharp.

You may have to move the target closer to the camera or furthur away from the camera to get the target to be sharp in the viewfinder or monitor.

If you can make this happen without vignette, a groundglass adaptor which places the groundglass about 115mm to 150mm from the front of the lens should work.

There is no guarantee this will work on the HVX200 because I have not tested with one myself.

I have tested my own adaptor on a JVC HD100. This camera has the 82mm
filter mount.

Jack Davidson · December 23rd, 2006, 10:32 PM

Bob, you repeatedly astound me by giving the most thorough, yet down to earth instruction around. I wish there was an award for "most helpful person on a forum." You'd have my vote. Wishing you a very Merry Christmas.

-Jack

Bob Hart · December 24th, 2006, 06:12 PM

Jack.

Thank you for your kind thoughts and comments. My time on this project might be interpreted as delayed onset of misspent youth. In my callow days I was perhaps a little less enthused and motivated.

Also in my neighbourhood, the nearest film industry, such as it was, existed on the other side of the country, the prospect of being sent off to Vietnam was looming.

Fortunately for me, I lost the lottery and like a few others have a bit of a survival guilt about not having put my hand up when friends got nashoed.

At the time, other life priorities then prevailed and there was an entirely different subset of adventures in front of me.

For young people with an interest in the audio-visual arts, times could not be better in terms of affordabililty and networking, things I did not even dream about.

All the very best to you and your own this festive season and to others here at dvinfo.

May the true essence of the Christmas spirit prevail.

Regards all.

December 16th, 2006, 03:01 AM	#1
Lau Ho Ming Regular Crew Join Date: Nov 2006 Location: Hong Kong Posts: 81	Achromat for HVX200? I know that my school has 2 Panasonic HVX200. But they don't officially offer to students for projects in ordinary circumstance. So I may tell them about my 35mm adapter and hope that they are interested with what I have done. So I will get a 58mm achromat for PD170 (Which is readily available for use). But is it too small for the HVX? What will happen if I use step-down rings.Notice that I'm a really poor student and can't even afford an large achromat e.g. 77mm, not to mention a camera.

December 23rd, 2006, 07:52 PM	#4
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	If you can get hold of the HVX200 for a few minutes test you can try something. Find a piece of thin cardboard. Cereal or biscuit packet is okay. Cut out a circle 82mm diameter on outside and 48mm inside diameter. 48mm is the internal diameter of the rear optical path of the +7 Century lens. To this circular piece of cardboard I will now give a name "cardboard pattern" Support the cardboard pattern across the front of the filter mount with tape, not inside the filter mount. If the cardboard pattern goes inside the filter mount, it will be closer to the camcorder lens and will spoil this test. If the camera has an underscan viewfinder, power the camera up and select underscan on the viewfinder. If it does not have an underscan viewfinder, you will have to find an underscan monitor and connect the camera to it. When the camera is running, adjust the zoom lens to wide. You will see the vignette the cardboard pattern will cause. Slowly zoom in. If the vignette is outside of the frame by zoom position 32mm, the +7 is likely to work on this camera for a frame wider than 24mm on the groundglass. A wide frame is going to give you problems with hot spot (corner brightness fall-off). If you want to use a wide frame, you will need to use condensor lenses to fix this problem. If your camera zoom can go to 54mm or higher number, you should be able to zoom closer on the groundglass to a smaller image, 24mm or slightly smaller. If you are happy to use a smaller groundglass area, this will fix the hotspot problem. If your camera can pass this test, borrow or buy a cheap 58mm mount Hoya close-up lens set for another test. Barcode number for this is " 0 24066 58021 4 " The Hoya kit contains three lenses, +1; +2; +4. These stacked together will give you +7 for testing. The image will be not good for production but good enough for this test. You will need another person to help you with this test. Draw a 24mm x 18mm target on a paper or cardboardwith thick felt tip marker pen. Draw this target with cross lines to make a grid. Don't make it all one colour because you need the lines to see if there is sharp focus or not. Screw all the lenses together. The +1 should be closest to camera, next is +2 then +4. Fit the camera on a tripod. Set the camera lens focus on about 1.8 metres. Place the target about 150mm from front of camcorder lens. The centre of the target must be exactly aligned with centre axis of camera lens. Fit your cardboard pattern in back of the Hoya lens stack. Hand hold the Hoya lens stack and offer this up to the camera using the cardboard pattern to make the position centred correctly. In the camera viewfinder or monitor, your should see your 24mm x 18mm target. Ask your assistant to adjust focus and zoom until your target comes in close enough to fill the frame side to side and is clear and sharp. You may have to move the target closer to the camera or furthur away from the camera to get the target to be sharp in the viewfinder or monitor. If you can make this happen without vignette, a groundglass adaptor which places the groundglass about 115mm to 150mm from the front of the lens should work. There is no guarantee this will work on the HVX200 because I have not tested with one myself. I have tested my own adaptor on a JVC HD100. This camera has the 82mm filter mount. Last edited by Bob Hart; December 24th, 2006 at 01:31 AM.

December 23rd, 2006, 10:32 PM	#5
Jack Davidson New Boot Join Date: Apr 2005 Location: Milwaukee, WI Posts: 23	Bob! Bob, you repeatedly astound me by giving the most thorough, yet down to earth instruction around. I wish there was an award for "most helpful person on a forum." You'd have my vote. Wishing you a very Merry Christmas. -Jack

December 16th, 2006, 03:58 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	I have tested a 7+ Century Optics achromatic dioptre with 58mm filter thread mount on an older Panasonic DVX100 with a home made 58mm to 72mm step-up ring. This I used with my own flip adaptor for 24mm x 18mm 4:3 frame and it worked okay into the DVX100. I don't know what the lens on the HVX200 is. What matters is how wide the front glass on the HVX is. The filter mounts are wider so no vignette gets into the image when the zoom lens on wide. If the HVX200 lens can zoom in at least to 54mm and if the HVX200 uses a 1/3" CCD, a 58mm 7+ achromatic dioptre has a chance of working. I don't know about a 4+. The 4+ does work on a Sony FX1 with lens zoom all the way in to 54mm for 24mm wide groundglass image. The adaptor has to be very long about 200mm for a 4+ dioptre onto a 24mm wide groundglass image. All the clips posted by agus35monk at YouTube have vision shot with a +7 dioptre used on a PD150 or FX1 type camera. The "b-movie heroes" clip has Letus35 footage as the close-up roving cam. Only the very first image of the microphone is Agus35 image in that clip.

December 23rd, 2006, 04:27 PM	#3
Lau Ho Ming Regular Crew Join Date: Nov 2006 Location: Hong Kong Posts: 81	The HVX200 has 82mm(It's huge...) filter mount. If I use have to step it down from 82 to 58 mm. Will it cause vignette with proper zoom through?

December 24th, 2006, 06:12 PM	#6
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	Jack. Thank you for your kind thoughts and comments. My time on this project might be interpreted as delayed onset of misspent youth. In my callow days I was perhaps a little less enthused and motivated. Also in my neighbourhood, the nearest film industry, such as it was, existed on the other side of the country, the prospect of being sent off to Vietnam was looming. Fortunately for me, I lost the lottery and like a few others have a bit of a survival guilt about not having put my hand up when friends got nashoed. At the time, other life priorities then prevailed and there was an entirely different subset of adventures in front of me. For young people with an interest in the audio-visual arts, times could not be better in terms of affordabililty and networking, things I did not even dream about. All the very best to you and your own this festive season and to others here at dvinfo. May the true essence of the Christmas spirit prevail. Regards all.