GH2 lensing question at DVinfo.net

Brian Luce · March 26th, 2011, 02:24 AM

100mm is a common line of demarcation for telephoto lenses in terms of when some of the unique characteristics of telephoto manifest -- such as image compression and DOF amplification. So how do we regard the 100mm on a GH2? with the crop factor is the line of demarcation around 50mm? The cropping effect on the GH2 isn't technically a telephoto effect. So what's the story here?

Joe Ogiba · March 29th, 2011, 06:53 AM

My 50mm F1.4 Pentax lens works great on my GH2 as a 100mm FF/35mm eqiv lens.

Jeff Harper · March 29th, 2011, 07:37 AM

That's a good question, but to clarify, are you asking if the depth of field characteristics of a lens changes because of the crop factor?

I would suspect not, but would love to know the answer.

A 100mm full frame lens becomes 200mm, that much we know, so maybe the depth of field properties are somehow magnified also.

Les Wilson · March 29th, 2011, 10:23 AM

This has been discussed but I can't locate where I saw it. Basically, the DOF is a function of the lens focal length irrespective of crop. Crop affects the FOV. As I understand it, the GH2's ETC is just another "crop". Here's a discussion that may be informative:
http://www.dvinfo.net/forum/canon-eo...eeper-dof.html

Brian Luce · March 29th, 2011, 03:19 PM

Actually I'm not so much talking about DOF. Focal length, as has been mentioned, doesn't have much to do directly with DOF. I'm thinking of other characteristics of long lenses, such as compression, and if cropping relates to it in the exact way that the actual glass does.

For example, let's say I'm filming a scene of someone trapped in small cave, I want everything to seem claustrophobic and tight, so I want to compress the background to help achieve that. Does the crop effect influence the shot? Or does my 100mm perform identically to same lens on a FF cam in terms of compression?

Jeff Harper · March 30th, 2011, 08:58 AM

If you don't find an answer here go to Photography community, including forums, reviews, and galleries from Photo.net and find the forum for your lens. Place is full of pros who will know the answer to your question. If you're using a Canon FD lens, there is an FD forum there. That's where I go for these issues.

March 26th, 2011, 02:24 AM	#1
Brian Luce Inner Circle Join Date: Jan 2006 Posts: 2,290	GH2 lensing question 100mm is a common line of demarcation for telephoto lenses in terms of when some of the unique characteristics of telephoto manifest -- such as image compression and DOF amplification. So how do we regard the 100mm on a GH2? with the crop factor is the line of demarcation around 50mm? The cropping effect on the GH2 isn't technically a telephoto effect. So what's the story here?

March 29th, 2011, 06:53 AM	#2
Joe Ogiba Regular Crew Join Date: Sep 2009 Location: Millstone,NJ Posts: 194	Re: GH2 lensing question My 50mm F1.4 Pentax lens works great on my GH2 as a 100mm FF/35mm eqiv lens. First test GH2 with 50mm F1.4 Pentax FA lens @F4 on Vimeo

March 29th, 2011, 07:37 AM	#3
Jeff Harper Inner Circle Join Date: Jun 2005 Location: Cincinnati, OH Posts: 8,425	Re: GH2 lensing question That's a good question, but to clarify, are you asking if the depth of field characteristics of a lens changes because of the crop factor? I would suspect not, but would love to know the answer. A 100mm full frame lens becomes 200mm, that much we know, so maybe the depth of field properties are somehow magnified also. __________________ "The horror of what I saw on the timeline cannot be described."

March 29th, 2011, 10:23 AM	#4
Les Wilson Inner Circle Join Date: Jan 2004 Location: Boca Raton, FL Posts: 3,014	Re: GH2 lensing question This has been discussed but I can't locate where I saw it. Basically, the DOF is a function of the lens focal length irrespective of crop. Crop affects the FOV. As I understand it, the GH2's ETC is just another "crop". Here's a discussion that may be informative: http://www.dvinfo.net/forum/canon-eo...eeper-dof.html

March 29th, 2011, 03:19 PM	#5
Brian Luce Inner Circle Join Date: Jan 2006 Posts: 2,290	Re: GH2 lensing question Actually I'm not so much talking about DOF. Focal length, as has been mentioned, doesn't have much to do directly with DOF. I'm thinking of other characteristics of long lenses, such as compression, and if cropping relates to it in the exact way that the actual glass does. For example, let's say I'm filming a scene of someone trapped in small cave, I want everything to seem claustrophobic and tight, so I want to compress the background to help achieve that. Does the crop effect influence the shot? Or does my 100mm perform identically to same lens on a FF cam in terms of compression?

March 30th, 2011, 08:58 AM	#6
Jeff Harper Inner Circle Join Date: Jun 2005 Location: Cincinnati, OH Posts: 8,425	Re: GH2 lensing question If you don't find an answer here go to Photography community, including forums, reviews, and galleries from Photo.net and find the forum for your lens. Place is full of pros who will know the answer to your question. If you're using a Canon FD lens, there is an FD forum there. That's where I go for these issues. __________________ "The horror of what I saw on the timeline cannot be described."