XH A1 close focus capabilities? at DVinfo.net

Toenis Liivamaegi · November 24th, 2006, 08:03 AM

I was wondering that maybe A1 can be focused to 36x24mm or smaller frame without an expensive achromat as it has quite good close focusing capabilities?

My cad simulation shows that at the widest angle in can focus on 36x24mm frame from ca 25mm but minimum distance required to get rid of vignetting in dof adaptor assembly is somewhere at 50mm.

Can someone please test if A1 can focus a 36x24mm or smaller frame from 50mm to 64mm distance? Focusing on 32x20 frame at 64mm would be perfect.

Thanks in advance,
T

Chris Hurd · November 24th, 2006, 10:39 AM

The best I could do for you quickly is a 58mm by 36mm target (the world's smallest Chroma DuMonde!) handheld at a distance of approximately 50mm with a focal length of Z50 (halfway through the zoom range). The other image is the edge of a ruler placed right against the front of the A1 lens bayonet mount... a distance of about maybe 9 or 10mm to the front objective. The width of the image is about 48mm, considerable less than the width of the front objective itself (which is 72mm). Hope this helps,

November 24th, 2006, 08:03 AM	#1
Toenis Liivamaegi Major Player Join Date: Nov 2005 Location: Tartu, Estonia Posts: 579	XH A1 close focus capabilities? I was wondering that maybe A1 can be focused to 36x24mm or smaller frame without an expensive achromat as it has quite good close focusing capabilities? My cad simulation shows that at the widest angle in can focus on 36x24mm frame from ca 25mm but minimum distance required to get rid of vignetting in dof adaptor assembly is somewhere at 50mm. Can someone please test if A1 can focus a 36x24mm or smaller frame from 50mm to 64mm distance? Focusing on 32x20 frame at 64mm would be perfect. Thanks in advance, T Last edited by Toenis Liivamaegi; November 24th, 2006 at 09:01 AM.

November 24th, 2006, 10:39 AM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	The best I could do for you quickly is a 58mm by 36mm target (the world's smallest Chroma DuMonde!) handheld at a distance of approximately 50mm with a focal length of Z50 (halfway through the zoom range). The other image is the edge of a ruler placed right against the front of the A1 lens bayonet mount... a distance of about maybe 9 or 10mm to the front objective. The width of the image is about 48mm, considerable less than the width of the front objective itself (which is 72mm). Hope this helps, Attached Thumbnails __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!