Macro lens suggestion for a pd-170 adapter at DVinfo.net

Gustavo Godinho · April 4th, 2005, 07:45 AM

Is it possible to suggest an exact macro len for a PD-170, though I don´t have an especific project of adapter yet?

Bob Hart · April 5th, 2005, 07:37 AM

Gustavo.

I have tested the Century Optics 7+ achromatic dioptre 58mm filter thread mount from my PD150 on a PD170 with the AGUS version I built and it works fine. Its not cheap but with a good 5 micron finished groundglass and good SLR prime lens preferable f1.8, you will get resolution on a test pattern up to limit of the PD150/PD170 of 530 TV lines. In the real world yourn results will not be as good unless you are really careful in setting up your focus on both your SLR still-camera lens and the relay stage between groundglass and camcorder.

Images from my experiments from first to most recent maccina can be found at www.dvinfo.net/media/hart

I made mine from PVC sewer pipes and caps but the most practical design which can be expected to work from the beginning is the project box version. I can't recall the exact web address but I think it is published on www.diaspora.net or and address something like that. Search here for messages by Jim Lafferty and I think you will find it.

My own sewer pipe version until it fell to pieces last week was a prism erecting device. If you use the +7 on a device which does not erect the image, your groundglass will be about 5 inches or 120mm away from the front of the dioptre lens.

If you do not want to eventually make a prism version, I believe you can use a stronger lens up to +10. Beyond that power, the job becomes harder. A +10 cannot be used with a prism version because the optical path becomes too short for the prism to fit between the groundglass and lens on front of camcorder.

For the first non-erecting AGUS I built, I used a very powerful lens set from a telescope eyepiece. The lens set is generic from mainland China and fits the Tasco telescope. It has the product number SW5042. It's optical characteristic is 2" 50mm eyepiece.

This lens set must be put into a new custom holder and the glass closest to the eye must also be now closest to the groundglass. This lens places the groundglass only about 18mm away from the front of this lens. It is very-very hard to set up and only just good enough to get a full frame on the 24mm x 18mm 4:3 35mm motion picture movie frame. It gives good light across the full frame but is not quite as sharp as the Century Optics 7+.

Your PD170 like the PD150 also has a design characteristic which can make life difficult when you set up centres. The CCD is not centred on the lens opticval centre. It is offset to one side. To demonstrate this, put the camcorder on a tripod, zoom to close. Frame on something like a doorknob in the exact centre of frame, lock the tripod firm, then zoom all the way out to wide. The doorknob will move offcentre. When you set up your optical centres for your SLR lens mount and your camcorder mount, you need to be aware of this. Although it is no big deal, it will affect the centre of the groundglass image depending how far you have to zoom in and you may find vignetting or dark edges from hot spotting on the left corners if you use a small aperture SLR lens.

With the +7 you will find you have to zoom in about 65% to 70%. Any furthur zoom in than this and the camcorder's low light performance drops off and you will also get a slightly darker margin on the corners. You can set up your centres with the camcorder zoomed in to about 65% to 70%. I preferred to keep the optical centres of the camcorder lens and the SLR lens on the same axis.

Good luck and enjoy your project.

April 4th, 2005, 07:45 AM	#1
Gustavo Godinho Regular Crew Join Date: Feb 2004 Location: Belém - Pa - Brazil Posts: 130	Macro lens suggestion for a pd-170 adapter Is it possible to suggest an exact macro len for a PD-170, though I don´t have an especific project of adapter yet? __________________ lml

April 5th, 2005, 07:37 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Gustavo. I have tested the Century Optics 7+ achromatic dioptre 58mm filter thread mount from my PD150 on a PD170 with the AGUS version I built and it works fine. Its not cheap but with a good 5 micron finished groundglass and good SLR prime lens preferable f1.8, you will get resolution on a test pattern up to limit of the PD150/PD170 of 530 TV lines. In the real world yourn results will not be as good unless you are really careful in setting up your focus on both your SLR still-camera lens and the relay stage between groundglass and camcorder. Images from my experiments from first to most recent maccina can be found at www.dvinfo.net/media/hart I made mine from PVC sewer pipes and caps but the most practical design which can be expected to work from the beginning is the project box version. I can't recall the exact web address but I think it is published on www.diaspora.net or and address something like that. Search here for messages by Jim Lafferty and I think you will find it. My own sewer pipe version until it fell to pieces last week was a prism erecting device. If you use the +7 on a device which does not erect the image, your groundglass will be about 5 inches or 120mm away from the front of the dioptre lens. If you do not want to eventually make a prism version, I believe you can use a stronger lens up to +10. Beyond that power, the job becomes harder. A +10 cannot be used with a prism version because the optical path becomes too short for the prism to fit between the groundglass and lens on front of camcorder. For the first non-erecting AGUS I built, I used a very powerful lens set from a telescope eyepiece. The lens set is generic from mainland China and fits the Tasco telescope. It has the product number SW5042. It's optical characteristic is 2" 50mm eyepiece. This lens set must be put into a new custom holder and the glass closest to the eye must also be now closest to the groundglass. This lens places the groundglass only about 18mm away from the front of this lens. It is very-very hard to set up and only just good enough to get a full frame on the 24mm x 18mm 4:3 35mm motion picture movie frame. It gives good light across the full frame but is not quite as sharp as the Century Optics 7+. Your PD170 like the PD150 also has a design characteristic which can make life difficult when you set up centres. The CCD is not centred on the lens opticval centre. It is offset to one side. To demonstrate this, put the camcorder on a tripod, zoom to close. Frame on something like a doorknob in the exact centre of frame, lock the tripod firm, then zoom all the way out to wide. The doorknob will move offcentre. When you set up your optical centres for your SLR lens mount and your camcorder mount, you need to be aware of this. Although it is no big deal, it will affect the centre of the groundglass image depending how far you have to zoom in and you may find vignetting or dark edges from hot spotting on the left corners if you use a small aperture SLR lens. With the +7 you will find you have to zoom in about 65% to 70%. Any furthur zoom in than this and the camcorder's low light performance drops off and you will also get a slightly darker margin on the corners. You can set up your centres with the camcorder zoomed in to about 65% to 70%. I preferred to keep the optical centres of the camcorder lens and the SLR lens on the same axis. Good luck and enjoy your project.