Problem with lens mount adapter (mamiya645/B4) at DVinfo.net

David C Wright · March 22nd, 2009, 08:09 AM

I have been testing a new lens adapter that allows me to use a Mamiya 645 lens on a B4 mount. It works great with lenses up to 200mm but the image is soft with my 300mm & 500mm. Both seem to work fine on a Mamiya stills camera. I am wondering if anyone has an idea of what might be going on? It is not a focus issue so much as a general softness across the whole picture. Thanks

David Wright
www.lunaseafilms.com

David W. Jones · March 22nd, 2009, 08:33 AM

You might consider posting what camera / adapter / Lens / you are using for a troubleshooting starting point.

David C Wright · March 22nd, 2009, 09:06 AM

Camera - Panasonic HDX900
lens- Mamiya 645, 100mm & 210mm- work well
300mm & 500mm- soft images (not focus, just a general softness)
Adapter- Mechanical adapter allowing Mamiya 645 lens to be fitted on a B4 mount (no optics)

David W. Jones · March 22nd, 2009, 01:29 PM

If I remember correctly, an adapter like that without optics will give you a 6.8 X crop,
and is best suited for macro use. Which means not all lenses will focus to infinity, and some will be unusable.

David C Wright · March 22nd, 2009, 03:11 PM

I am actually on my third adapter and have had them made progressively thinner until I have one that does focus to infinity. My confusion lies around the fact that the longer lenses do not seem to work, focused on a subject that is close or far away.

March 22nd, 2009, 08:09 AM	#1
David C Wright Regular Crew Join Date: Mar 2005 Location: Appleton, ME Posts: 160	Problem with lens mount adapter (mamiya645/B4) I have been testing a new lens adapter that allows me to use a Mamiya 645 lens on a B4 mount. It works great with lenses up to 200mm but the image is soft with my 300mm & 500mm. Both seem to work fine on a Mamiya stills camera. I am wondering if anyone has an idea of what might be going on? It is not a focus issue so much as a general softness across the whole picture. Thanks David Wright www.lunaseafilms.com

March 22nd, 2009, 09:06 AM	#3
David C Wright Regular Crew Join Date: Mar 2005 Location: Appleton, ME Posts: 160	Equipment info Camera - Panasonic HDX900 lens- Mamiya 645, 100mm & 210mm- work well 300mm & 500mm- soft images (not focus, just a general softness) Adapter- Mechanical adapter allowing Mamiya 645 lens to be fitted on a B4 mount (no optics)

March 22nd, 2009, 03:11 PM	#5
David C Wright Regular Crew Join Date: Mar 2005 Location: Appleton, ME Posts: 160	Infinity I am actually on my third adapter and have had them made progressively thinner until I have one that does focus to infinity. My confusion lies around the fact that the longer lenses do not seem to work, focused on a subject that is close or far away.

March 22nd, 2009, 08:33 AM	#2
David W. Jones Trustee Join Date: Dec 2006 Location: Little Rock Posts: 1,383	You might consider posting what camera / adapter / Lens / you are using for a troubleshooting starting point.

March 22nd, 2009, 01:29 PM	#4
David W. Jones Trustee Join Date: Dec 2006 Location: Little Rock Posts: 1,383	If I remember correctly, an adapter like that without optics will give you a 6.8 X crop, and is best suited for macro use. Which means not all lenses will focus to infinity, and some will be unusable.