Dof Adapter problems at DVinfo.net

Jordi Dusanek · June 15th, 2009, 03:41 PM

Hello,

recently I've bought a cheap 35mm adapter (don't have money for a professional one, and my DIY skills are catastrophic). It comes with basic rods, the adapter and an achromat. It's a Nikon mount so I tried with a 30-70mm lens, and there is something strange going on.

There is a very heavy distortion in the edges of the image. I don't know if it is what people call barrel distortion. I think it's the achromat's fault, and that I need a better one, but before buying anything more I want to be sure.

Also the image isn't really very clear o sharp, ¿is that because of the focusing screen?.

Here is the video:

RapidShare: Easy Filehosting

It's my first time using a 35mm adapter, so any help will be great.

Jordi

Christopher Glavan · June 15th, 2009, 06:05 PM

Jordi,

I refuse to tell you that you should have just saved your money and bought a more expensive model, because I think that's a cop-out answer. I firmly believe you should spend as little as necessary to get the job done the way you want it. I'm also sure you already know the caveat to that-- you get what you pay for.

Having had no personal experience with dof adapters, please take my comments with a grain of salt. That said, I am interested in dof adapters for use with my camera and have read a lot. Sounds to me like you have a combination of at least a couple of things happening. First, my guess is your ground glass/achromat is either of poor quality, or not positioned correctly for your camera. Also, a lot of the cheaper adapters seem to share the same achilles heel: light loss. Believe it or not, I've seen adapters that darken the camera's image a full three stops!

I would suggest trying to find a better quality ground glass/achromat that will fit your setup. If that doesn't work, I'm not sure what to tell you (again, no personal experience). You could try tinkering with the position of the glass, but I would rule out everything else first.

HTH,

Chris

Jordi Dusanek · June 16th, 2009, 10:11 AM

Thank you Christopher for your response. As you've said, I only want this for some shots, and spending 900 euros on a better adapter is an option I don't actually have (I don't have 900 euros to spend). So I bought this cheap adapter, the price was like the materials for a DIY model, but all CNC machined.

I knew that it won't work out-of-the-box (there is no box anyway), so now I'm figuring out what I need in order to get it working in a basic level.

¿Should I begin with the achromat or the gg?

Cameron Frittz · June 20th, 2009, 11:06 PM

Jordi. could you link us to the actual adapter?

Jordi Dusanek · June 22nd, 2009, 05:33 AM

Hello Cameron,

the adapter is this one:

Welcome! Cineadapter~

The've send me the thing with an 82mm ring. With shipping it was about 280 euros.

June 15th, 2009, 03:41 PM	#1
Jordi Dusanek Regular Crew Join Date: Aug 2005 Posts: 38	Dof Adapter problems Hello, recently I've bought a cheap 35mm adapter (don't have money for a professional one, and my DIY skills are catastrophic). It comes with basic rods, the adapter and an achromat. It's a Nikon mount so I tried with a 30-70mm lens, and there is something strange going on. There is a very heavy distortion in the edges of the image. I don't know if it is what people call barrel distortion. I think it's the achromat's fault, and that I need a better one, but before buying anything more I want to be sure. Also the image isn't really very clear o sharp, ¿is that because of the focusing screen?. Here is the video: RapidShare: Easy Filehosting It's my first time using a 35mm adapter, so any help will be great. Jordi

June 15th, 2009, 06:05 PM	#2
Christopher Glavan Major Player Join Date: Aug 2008 Location: Redding, CA Posts: 260	Jordi, I refuse to tell you that you should have just saved your money and bought a more expensive model, because I think that's a cop-out answer. I firmly believe you should spend as little as necessary to get the job done the way you want it. I'm also sure you already know the caveat to that-- you get what you pay for. Having had no personal experience with dof adapters, please take my comments with a grain of salt. That said, I am interested in dof adapters for use with my camera and have read a lot. Sounds to me like you have a combination of at least a couple of things happening. First, my guess is your ground glass/achromat is either of poor quality, or not positioned correctly for your camera. Also, a lot of the cheaper adapters seem to share the same achilles heel: light loss. Believe it or not, I've seen adapters that darken the camera's image a full three stops! I would suggest trying to find a better quality ground glass/achromat that will fit your setup. If that doesn't work, I'm not sure what to tell you (again, no personal experience). You could try tinkering with the position of the glass, but I would rule out everything else first. HTH, Chris __________________ Reel Impressions Media - Make it more than a memory GY-HD100- 7D- PSC Promix 3- Lectro/Sennheiser- Zoom H4- MPB- CS6/CC

June 16th, 2009, 10:11 AM	#3
Jordi Dusanek Regular Crew Join Date: Aug 2005 Posts: 38	Thank you Christopher for your response. As you've said, I only want this for some shots, and spending 900 euros on a better adapter is an option I don't actually have (I don't have 900 euros to spend). So I bought this cheap adapter, the price was like the materials for a DIY model, but all CNC machined. I knew that it won't work out-of-the-box (there is no box anyway), so now I'm figuring out what I need in order to get it working in a basic level. ¿Should I begin with the achromat or the gg?

June 20th, 2009, 11:06 PM	#4
Cameron Frittz Regular Crew Join Date: Jan 2009 Location: Astoria, NY Posts: 45	Jordi. could you link us to the actual adapter?

June 22nd, 2009, 05:33 AM	#5
Jordi Dusanek Regular Crew Join Date: Aug 2005 Posts: 38	Hello Cameron, the adapter is this one: Welcome! Cineadapter~ The've send me the thing with an 82mm ring. With shipping it was about 280 euros.