View Full Version : GY-HD100 Depth of Field adapter?


Richard Robertson
November 13th, 2009, 08:43 AM
I found this part on ebay, supposedly it allows a user to attach this piece to the camera and then you would be able to attach M42 threaded lenses to your camera giving the user a great depth of field just like an SLR camera. Anybody know anything about these, or if they are legit. I have pasted a link below.

Rich

http://cgi.ebay.com/PRO-1-3-adapter-SONY-HVR-or-JVC-GY-HD-HM-M42_W0QQitemZ370283281504QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item56369a7c60#ht_2880wt_1155

Matt Lehman
November 13th, 2009, 09:09 AM
Did you read the English on that ad? LOL!

I'd be extremely skeptical of this one. First of all there appears to be no glass in that adapter not to mention it's length is much too short. I believe if it does anything it would be to directly attach a lens to the JVCs. This would (without correcting glass, etc.) in short only work to magnify the image projected onto the imager. So, you would not be gaining any true DOF with this adapter IMHO.

Shaun Roemich
November 13th, 2009, 10:18 AM
This would behave as Matt describes - the focal length of any lens attached would remain the same and therefore would turn any ciné lens attached into a telephoto lens with no beneficial short depth of field characteristics. Without a focusing plane internally, this adaptor would still use the size of the JVC 1/3" imagers.

Having said that, if you need tremendous telephoto and have M42 mount lenses just kicking around... Didn't think so...

Chris Davis
November 13th, 2009, 11:13 AM
There is nothing in that auction description that claims this is a DOF adapter. It is simply an adapter to allow mounting Arri standard lenses on a JVC HD100/110/200.

Don't paint this guy as a scammer when you are just assuming something that was never claimed.

Tim Dashwood
November 13th, 2009, 11:23 AM
The ad says it is an Arri mount, not M42. This would be for old Arri Bayonet style lenses.

Richard Robertson
November 13th, 2009, 11:57 AM
I should have clarified better. I realize that this isn't in any way a DOF adapter. What I was trying to say is, is this some type of 1/3 mount allowing external lenses such as a m42 or nikon or something like that to be hooked directly to the camera. I choose the wrong auction this was for an Arri, they had another one for a M42 threaded lens. I see that it amplifies the image by 7x. Lets re state the question another way. Is there another way with this camera of gaining greater depth of field without dumping $1500-$2000 for a 35mm DOF adapter kit. I spent that money for my DVX100 and bought one, of course it is a different size needed for the JVC, but honestly I am a little disappointed with the end result. The time spent getting everything just right for a shot makes shooting with these things incredibly long, unless I am doing something wrong here. Any help would be appreciated. Again sorry about the confusion before, lost my brain for a bit there.

John Mitchell
November 17th, 2009, 12:44 AM
If you do a little research there are threads around here on home made DOF adapters. If you already own a good quality DOF adpter for your DVX you might find that a decent relay lens to hook up that adapter to the JVC is the way to go.

Letus make one but it isn't cheap .. more than their DOF adapters. And I don't know if it would work with other brands...

Letus 1/3" Relay (Full Frame)*::*Letus Relay Lenses*::*LetusDirect (http://www.letusdirect.com/cart/letus-one-third-inch-relay.html)

Only this kind of solution allows the camera to stay in it's current form factor (total lens length is about the same as with the stock Fuji). You can also probably get an achromat that will allow you to attach your current DOF to the front of the stock lens but I think the whole setup gets very unweildy..

There is also JVC's own COPLA adapter designed for 16mm lenses. Once again not cheap.

Brian Standing
November 29th, 2009, 08:19 AM
You have to remember that depth of field results from an interplay between the focal length, aperture and the size of the imaging sensor. If these three things are the same, your depth of field will always be the same. Small sensors like the JVC's 1/3" sensor inherently have a deeper depth of field than larger sensors or 35mm film. Attaching an 80mm Nikon, Arri or M42 lens to your JVC will give you exactly the same depth of field as the stock Fujinon lens at 80mm. As long as focal length, aperture and sensor size remain the same, the only difference between lenses will be subtle variations in bokeh, aberration, color and focus.

The main use of the simple mechanical SLR lens mounts for your JVC is that it gives you an economical way to access the extreme telephoto range of lens options. A 200mm lens focused on a 1/3" sensor, for example, gives you the same field of view as a 1400mm lens would mounted on a 35mm film SLR. This is great for wildlife, surfing competitions, or looking at the moon, but not so practical for other situations.

The expensive depth of field adaptors include optics that refocus the image of an attached lens onto a ground glass screen. Rather than go that route, if I were you, I'd take a look a the new crop of HD video-capable digital SLR cameras. I'm thinking of picking up a Pentax K-X (about $600) as a b-cam for my HD100. It does 1280x720 24p, the same as my JVC HD cam, has no recording length limitations and looks to have very good image and low-light characteristics. For b-roll, it doesn't matter to me that the K-X doesn't have a mic input. I think these HD DSLRs have, or shortly will, make the lens adaptors obsolete.

Stephen J. Williams
December 5th, 2009, 10:42 AM
I'm thinking of picking up a Pentax K-X (about $600) as a b-cam for my HD100. It does 1280x720 24p, the same as my JVC HD cam, has no recording length limitations and looks to have very good image and low-light characteristics. For b-roll, it doesn't matter to me that the K-X doesn't have a mic input. I think these HD DSLRs have, or shortly will, make the lens adaptors obsolete.


Brian... This looks like a great idea. I might do the same after checking out the price and specs on B&H. Let us know how it works for a b cam if you end up picking one up.

Steve

Richard Robertson
December 11th, 2009, 04:27 PM
I sold the DVX100 on ebay last night, I will be buying the camera on Monday when the paypal clears the bank. B&H photo has a deal, $649 with free shipping, you get the camera with stock lens 18 to 55mm and an additional 50 to 200mm. Really good deal. I guess I was asking too little for the camera, it sold on buy it now after only being on Ebay for 3 minutes.