Panasonic GF1 with M or Canon -mount lenses

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Archive 2010 · Panasonic GF1 with M or Canon -mount lenses

sebboh
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p.2 #1 · Panasonic GF1 with M or Canon -mount lenses

Bifurcator wrote:
I agree about the WA part of that statement. I mean, I don't see many 25mm f/0.7 lenses around - which would be needed to "perfectly" match the 50/1.4 on a FF. (although I have a 12.5mm f/1.2

) Still, I have to say I don't think I've seen any images on this site that I thought I couldn't duplicate the angle and DOF of - in general. There's a few I can't touch the DR of (without multiple exposures), and quite a few I would need to spend a lot of money to match the length-and-sharpness of... but... So which images are you talking about specifically?

http://www.fredmiranda.com/forum/topic/839374/10
scroll halfway down to teh_rebel's family shots. you could certainly achieve that level of dof with a longer lens on 4/3 but there is no way you could get the same level of isolation and include as much of the environment as is done in the middle two pictures.

there are also a bunch of shots just not possible with 4/3 in Piotr_P's shots of krakow 2/3 of the way down this page: http://www.fredmiranda.com/forum/topic/839374/28 and one from Denoir of some baby coots halfway down the same page.

Sep 10, 2010 at 02:03 PM

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p.2 #2 · Panasonic GF1 with M or Canon -mount lenses

Really? These: http://www.fredmiranda.com/forum/topic/839374/28#8762047 and these: http://www.fredmiranda.com/forum/topic/839374/10#8339945 ? Hmmm, well I'm going to have to prove it to myself because it's not obvious to me at this point. I think I'll do that today if it's not too hot. It's looking like a scorcher tho and I don't wanna break another GH1 by sweating on it.

cogitech wrote:
BIF,
The shots you posted are not comparable in any way whatsoever, which is why you are drawing such conclusions.

Why not? They're not that off I think. Same focus distance, same aperture affect according the math proposed here. Only the focal length is different - 55mm on the FF vs. 50mm on the M3/2 when it should be 50mm on the FF and 100mm on the M4/3. But I can guess those differences. Is there something else?

Keep in mind that I'm not thinking that there's no difference. Rather I think there's not enough difference to really even mention. Certainly not an "obvious" difference unless you're pulling out a ruler to measure the blur length or something. At least that's my thinking at this point. No?

Sep 11, 2010 at 12:32 AM

sebboh
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p.2 #3 · Panasonic GF1 with M or Canon -mount lenses

Bifurcator wrote:
Really? These: http://www.fredmiranda.com/forum/topic/839374/28#8762047 and these: http://www.fredmiranda.com/forum/topic/839374/10#8339945 ? Hmmm, well I'm going to have to prove it to myself because it's not obvious to me at this point. I think I'll do that today if it's not too hot. It's looking like a scorcher tho and I don't wanna break another GH1 by sweating on it.

yep, pictures 2 & 3 in both posts. i will be extremely surprised if you can come close (bear in mind i have a 4/3 camera so i feel i have a good sense of what can be achieved). you have to match the field of view (this means an 18mm lens or wider on 4/3).

Bifurcator wrote:
cogitech wrote:
BIF,
The shots you posted are not comparable in any way whatsoever, which is why you are drawing such conclusions.

Why not? They're not that off I think. Same focus distance, same aperture affect according the math proposed here. Only the focal length is different - 55mm on the FF vs. 50mm on the M3/2 when it should be 50mm on the FF and 100mm on the M4/3. But I can guess those differences. Is there something else?

all your shots are at a very short focus distance. every lens has a narrow dof at those distances even p&s lenses. the difference between 1cm of dof and 2cm of dof isn't that noticeable. if you focus out a few meters with a wide angle the difference is much more noticeable (3ft versus 7ft at a 12ft focal distance).

Sep 11, 2010 at 02:35 AM

gena_mak
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p.2 #4 · Panasonic GF1 with M or Canon -mount lenses

2X crop does not mean you multiply by 2.
Standard aperture scale goes in 2x increments like 2, 2.8, 4, 5.6... 2x means from 2 to 2.8 and not 4 and, it applies to DOF and, not to amount of light.

Sep 15, 2010 at 03:38 PM

jussihellsten
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p.2 #5 · Panasonic GF1 with M or Canon -mount lenses

sebboh wrote:
2 times the actual f number i believe not the amount of light

Sep 15, 2010 at 05:32 PM

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p.2 #6 · Panasonic GF1 with M or Canon -mount lenses

sebboh,

Yeah, if we insist on the exact same AOV then you're right. But if I can cheat a little by taking a step back with say a 24/1.4 or 1.8 then maybe not. And that's really what I'm talking about - achieving that same general affect - approximately and to the extent that no one would know any differences unless they were measuring for it or something. This is why I remain unconvinced. Sure if we make the rules that I have to use the exact same equipment with the same proximities then there's no hope but that's not about creating the effects (making the photograph) either. That becomes some kind of mathematical science project or something.

In the end so far, to date, I still think I'm better off just ignoring folks professing that there's "so much difference" between the DOF control of a FF vs. a M4/3rds sensor. I think there's some - but it's not noticeable to the general observer. Now the difference in DR sure can be! But that's yet another side-topic I guess.

Sep 15, 2010 at 06:38 PM

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p.2 #7 · Panasonic GF1 with M or Canon -mount lenses

If we use the standard DOF formula used by the typical depth of field calculators then yes it has to be 2 times the f-number. i.e. the 50mm 1.4 mounted on m4/3 will match the 100mm 2.8 lens on FF. However that formula is just an simplifying approximation of a more complicated geometric construction. The approximation is specially inaccurate towards the extremes i.e. very close distance and very far distances. I wonder if someone has ever taken the pain to go through the real calculations and investigate the sensor size versus DOF trade-off more accurately. Or alternatively if someone has systematically used test charts etc to practically measure the DOF differences between the two formats.

Off course there is also the matter that DOF is a very subjective measurement which depends on the viewing size and the notion of "acceptable sharpness".

A few weeks ago I will was comparing an S90 compact against a DSLR with the typical 18-55mm kit to see if the DSLR with kit lens offers any advantages over the advanced compacts in terms of high iso performance and DOF control. While I did not do any formal testing, I was pretty surprised to see that even towards the long end where s90 matches the aperture of the kit lens, I didn't see a significant DOF difference between the two. So I have started to suspect that there might be more to it than the simple linear scaling of DOF with sensor size

Sep 15, 2010 at 06:46 PM

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p.2 #8 · Panasonic GF1 with M or Canon -mount lenses

Yup, and that's a tiny little P&S sensor which even I will admit to a noticeable difference - having shot the Minolta A2 for as long as I did.

But mostly I just wanted to add to your sentence:

...DOF is a very subjective measurement which depends on the viewing size, crop factors, color and luminance contrast of the OOF scene items, the sharpness of in focus subjects, post processing choices, and the notion of "acceptable sharpness".

Sep 15, 2010 at 06:58 PM

sebboh
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p.2 #9 · Panasonic GF1 with M or Canon -mount lenses

curious80 wrote:
If we use the standard DOF formula used by the typical depth of field calculators then yes it has to be 2 times the f-number. i.e. the 50mm 1.4 mounted on m4/3 will match the 100mm 2.8 lens on FF. However that formula is just an simplifying approximation of a more complicated geometric construction. The approximation is specially inaccurate towards the extremes i.e. very close distance and very far distances. I wonder if someone has ever taken the pain to go through the real calculations and investigate the sensor size versus DOF trade-off more accurately. Or alternatively if someone has systematically used test charts etc to practically measure the DOF differences between the two formats.

i believe the simple 2x formula breaks down severely at very short focus distances (if my memory of the actual formula for dof serves). i'm sure somebody with too much time on their hands has done a thorough analysis of the effects of sensor size on dof in different shooting situations, but i'm not particularly interested in reading about it. the best way to find out if a format allows you enough dof control is to shoot with it for a week and see how you feel about the results. for me 4/3 allows plenty of dof control for about 80% of the kinds of shots i'd like to take. for about 10% of the remaining shots i'd like to take even FF would not give me enough dof control. the main failure of 4/3 for me is indoors at an effective focal length smaller than 40mm. in those very specific circumstances i cannot get the type of effect i would like.

Sep 15, 2010 at 07:50 PM

sebboh
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p.2 #10 · Panasonic GF1 with M or Canon -mount lenses

Bifurcator wrote:
sebboh,

Yeah, if we insist on the exact same AOV then you're right. But if I can cheat a little by taking a step back with say a 24/1.4 or 1.8 then maybe not. And that's really what I'm talking about - achieving that same general affect - approximately and to the extent that no one would know any differences unless they were measuring for it or something. This is why I remain unconvinced. Sure if we make the rules that I have to use the exact same equipment with the same proximities then there's no hope but that's not about creating the effects (making the photograph) either. That becomes some kind of mathematical science project or something.

there is a big difference (to me) between 35mm effective focal length and 50mm effective focal length and you can't always take a step back indoors. all i'm saying is there are some things that are very hard to do with 4/3 and if you try to do them you'll notice the difference (or at least i did). if you don't take those specific types of shots though it really doesn't matter.

Sep 15, 2010 at 07:56 PM

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