“Full Frame Equivalence” and Why It Doesn’t Matter

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Sagar
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p.2 #1 · “Full Frame Equivalence” and Why It Doesn’t Matter

Here is another article by a well known photographer on why sensor size matters

http://davidduchemin.com/2009/07/sensor-and-sensibility/

Feb 02, 2013 at 10:43 PM

Mescalamba
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p.2 #2 · “Full Frame Equivalence” and Why It Doesn’t Matter

mpmendenhall wrote:
Mescalamba wrote:
If you want to prove it to yourself, get some 67 lens and use it on FF or smaller. You will see that even when you used lets say 80mm lens, it doesnt look like 80mm for FF neither it does look like 80mm for APS-C. Thats reason why I own only FF lens.

I've used several lenses designed for 645 and 6x6 coverage on FF, and they behave exactly like their focal length and apertures would imply (regardless of "native" format). There are certainly manufacturer-specific differences in coatings, design, etc., giving different rendering styles just as there are differences between FF-native lenses, but in what way are you finding an 80mm lens to not be "80mm-ish"?

I guess then its matter of personal view. I saw quite a bit of pics taken with 67 105/2,4 that look like MF despite being shot at APS-C and not stitches. Maybe its just individual and not everyone sees that.

Feb 02, 2013 at 10:53 PM

Jman13
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p.2 #3 · “Full Frame Equivalence” and Why It Doesn’t Matter

The article wasn't written for FMers...you guys know this stuff. It is not meant to discourage the legitamate comparison if you are most familiar with full frame and find it convenient to think in those terms. Nor is it in any way meant to promote smaller formats...it's really a response to rabid fanboys on the opposite spectrum. I get crazy rabid comments and emails that effusively purport that all crop lenses are garbage, and the main justification for this is that smaller formats can't do as shallow depth of field. The times when more depth of field are desired, and thus many of the advantages of larger sensors are negated, are conveniently ignored.

As to the total light argument...the reason I bring it up is because in the real world it is nowhere a direct correlation to image quality based solely on sensor size. For the ratio to hold, it requires that the sensor technologies are the same, and have the same efficiencies, etc, which makes it valuable for approximating how one sensor design may scale with size, but is terrible as a blanket equivalence based on sensor size alone. I agree that the IS argument had no place in the discussion, and actually got on to remove it before coming here...it has since been removed.

Frankly, the crazy analogies by many (non FMers) became quite annoying. While in some cases, things are simplified due to trying to avoid getting bogged down in the weeds, I don't think there's anything factually incorrect.

You guys are not really the target audience. People here understand the relationships between formats and also understand its all about making the best image. Frankly, when the article went viral this morning, I kind of hoped it wouldn't get discussed here, as FM tends to stay out of this discussion most of the time, and it's refreshing. And that was the point....it'd be nice if everyone thought more like this crowd.

Feb 02, 2013 at 11:12 PM

michael49
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p.2 #4 · “Full Frame Equivalence” and Why It Doesn’t Matter

Jman13 wrote:
....as FM tends to stay out of this discussion most of the time, and it's refreshing. And that was the point....it'd be nice if everyone thought more like this crowd.

Agreed. Pleeeeese don't let this place turn into dpreview.

Feb 03, 2013 at 12:18 AM

douglasf13
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p.2 #5 · “Full Frame Equivalence” and Why It Doesn’t Matter

The bottom line is that, as I'm moving from format to format, I like to know what my equivalent focal length (for the field of view) and equivalent aperture (for depth of field) are, so both equivalences certainly matter. Sure, both sensor ratio and sensor technology differences don't make those equivalencies perfect, but it's useful to know them in general terms.

We all make concessions for size and convenience in one way or another, or we'd all be shooting 8x10, but, in terms of IQ, bigger is better is generally the case.

Feb 03, 2013 at 01:06 AM

naturephoto1
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p.2 #6 · “Full Frame Equivalence” and Why It Doesn’t Matter

douglasf13 wrote:
The bottom line is that, as I'm moving from format to format, I like to know what my equivalent focal length (for the field of view) and equivalent aperture (for depth of field) are, so equivalence certainly matters. Sure, both sensor ratio and sensor technology differences don't make those equivalencies perfect, but it's useful to know them in general terms.

We all make concessions for size and convenience in one way or another, or we'd all be shooting 8x10, but, in terms of IQ, bigger is better is generally the case.

Many of us that shot multiple format sizes would try to think in terms of equivalent focal lengths to aid in taking photos. I would tend to do this whether carrying 4" X 5", 6 X7, or 35mm camera systems.

Rich

Feb 03, 2013 at 01:15 AM

Johnny B Goode
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p.2 #7 · “Full Frame Equivalence” and Why It Doesn’t Matter

naturephoto1 wrote:
douglasf13 wrote:
The bottom line is that, as I'm moving from format to format, I like to know what my equivalent focal length (for the field of view) and equivalent aperture (for depth of field) are, so equivalence certainly matters. Sure, both sensor ratio and sensor technology differences don't make those equivalencies perfect, but it's useful to know them in general terms.

We all make concessions for size and convenience in one way or another, or we'd all be shooting 8x10, but, in terms of IQ, bigger is better is generally the case.

Many of us that shot multiple format sizes would try to think in terms of equivalent focal lengths to aid in taking photos. I would tend to do this whether carrying 4" X 5", 6 X7, or 35mm camera systems.

Rich

I think the better question is what distinguishes a new format from a crop of an image. It's confusing because crop sensored dslrs and 135 sized format dslrs share lenses (and to an extent, the market). I tend to view apsc as a smaller format and stay away from the "equivalent" FOV discussion. When shooting 6x6 MF you don't call your 38mm a 21mm or your 80mm a 50mm equivalent, do you?

Yes you're still shooting at the same apature on a crop sensor but to get the same FOV your subject needs to back up (or if you're a nice photographer you could offer to take the step back) and that increases the depth of field. Not bad just different. Medium format you're able to shoot at a closer distance to your subject to obtain the same field of view which increases the subject's separation from the background.

but i realize i'm preaching to the choir.

Feb 03, 2013 at 01:34 AM

Lee Saxon
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p.2 #8 · “Full Frame Equivalence” and Why It Doesn’t Matter

"Aperture equivalence" and "crop factor," the author is correct, don't make a lens or sensor format inferior. However, I don't think that means they "don't matter."

It's very important to be aware, so you can adjust accordingly, that a 2x crop of 50mm f/2 will have different perspective/rendering and increased depth of field compared to 100mm f/2.

Feb 03, 2013 at 02:44 AM

Tanegashima
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p.2 #9 · “Full Frame Equivalence” and Why It Doesn’t Matter

crazeazn wrote:
majority of the people who buy m4/3rd systems dont care about equivalence

+1

Half of the M4/3 shooters, shoot on full auto, the other half prefer to carry less and still have pretty good results, specially if shallow DOF or a high DR/SNR on low-light levels aren't required or important for the final picture...

Just like half of DSLR 35mm shooters, bought an expensive camera so they don't feel inferior, the other half, really have a use for those cameras/lenses.

IMHO, I think there's a big market push for 35mm cameras, because manufacturers know that if they sell these cameras, they'll also sell more expensive lenses to go with them.

There's also a big market push for a better quality/size compromisse, mainly in Asia, where even the Nikon 1 system is quite popular. And cameras the size of the X100 are considered big!

In my opinion, the perfect balance is APS-C mirrorless cameras with 1 stop faster lenses. Too bad I already made a big investment in Nikkor glass for FX... If I knew better some years ago...

Feb 03, 2013 at 02:54 AM

JohnJ
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p.2 #10 · “Full Frame Equivalence” and Why It Doesn’t Matter

Mescalamba wrote:
... look like MF despite being shot at APS-C and not stitches. ...

What you mean by that?

Mescalamba wrote:
... Maybe its just individual and not everyone sees that.

Is it like 3D which can only be seen by the elite and under special circumstances? Clearly I'm not one of them as I can't see 3D either.

Feb 03, 2013 at 03:23 AM

philip_pj
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p.2 #11 · “Full Frame Equivalence” and Why It Doesn’t Matter

Most discussions about 'pupil size' revolve around the epidemic of overweight schoolchildren, lol. I doubt we can craftily convince the buying public into boning up on, and actually caring about another arcane camera statistic.

Feb 03, 2013 at 03:26 AM

mpmendenhall
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p.2 #12 · “Full Frame Equivalence” and Why It Doesn’t Matter

philip_pj wrote:
Most discussions about 'pupil size' revolve around the epidemic of overweight schoolchildren, lol. I doubt we can craftily convince the buying public into boning up on, and actually caring about another arcane camera statistic.

I'm pretty sure "f-stop" is even more arcane. Entrance pupil size is one of the most obvious and easy to understand concepts about a lens: it's how big the hole in front is that light goes in --- unlike f-stop and focal length, you can actually see how big the light-hole is just by looking at the lens. And bigger = more light (unlike f-stop, where you have to figure out that small numbers are "better" by the inverse square). And it makes depth-of-field (in object space) easier to visualize by the light cone coming from the entrance pupil (instead of expecting folks to grok circles of confusion in microns on the image plane).

Feb 03, 2013 at 03:53 AM

Zaitz
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p.2 #13 · “Full Frame Equivalence” and Why It Doesn’t Matter

Johnny B Goode wrote:
When shooting 6x6 MF you don't call your 38mm a 21mm or your 80mm a 50mm equivalent, do you?

On the large format forums you can often read people saying things like that. I am always converting to a full frame equivalent because it is what I know. Rough calculation I do for a ballpark estimate:

8x10 focal length divided by 2 = 4x5 / 3 = 35mm / 1.52 = DX

Worse because a lot of them are in inches! So I first have to multiply it by 25.4. But I am better at knowing the field of view for 4x5 and 8x10 focal lengths now so I don't sit and convert everything.

Feb 03, 2013 at 04:49 AM

douglasf13
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p.2 #14 · “Full Frame Equivalence” and Why It Doesn’t Matter

Johnny B Goode wrote:
When shooting 6x6 MF you don't call your 38mm a 21mm or your 80mm a 50mm equivalent, do you?

I certainly think of them like that, but not always just relating to 35mm format. If I want to shoot something on my aps-c camera that is equivalent to my 80mm on 645, I know that I need about a 30mm or so lens, and, if I want similar depth of field wide open, I'd need f1.1-ish.

All that I'm saying is that, obviously, someone shooting multiple formats knows which lenses are wide, standard, tele, etc. on their various formats, as well as calculating the depth of field differences. Thinking about equivalents for different formats is pretty standard procedure, no?

Feb 03, 2013 at 05:21 AM

douglasf13
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p.2 #15 · “Full Frame Equivalence” and Why It Doesn’t Matter

Lee Saxon wrote:

It's very important to be aware, so you can adjust accordingly, that a 2x crop of 50mm f/2 will have different perspective/rendering and increased depth of field compared to 100mm f/2.

Actually, if you're standing in the same place and using a 50mm on m4/3 and a 100mm on 135, you'll basically have the same perspective, outside of the obvious ratio difference between the two formats. Like you said, though, the depth of field will be different.

Feb 03, 2013 at 05:25 AM

pr4photos
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p.2 #16 · “Full Frame Equivalence” and Why It Doesn’t Matter

I always want to know the equivelant, but thats probably because i come from a background of using large format, medium format, and 35mm format. It makes things a lot simpler, because I might want to change lens or format quickly and still get a similar angle of view. I now use m43 as well and it's essential I know that I double the lens mm to get the 35mm equivelant, ie when looking at wide angles it was very useful to know that the 14mm gives the same view as a 28mm 'full frame'. Am guessing at the end of the day it depends on your background

Feb 03, 2013 at 06:16 AM

redisburning
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p.2 #17 · “Full Frame Equivalence” and Why It Doesn’t Matter

gonna go with the people saying that it's useful.

50mm on my 4x5 is hilariously different than 50mm on my 35mm cameras. even on a 645 it's a huge difference. and since I only shoot with 50mm "equivalents" it's somewhat of an important distinction for me. I know the approximate FoV I am expecting to get and deviation from this leads to me being grumpy.

if this guy is happy with m4/3rds good for him. but his article is mostly a justification for not buying a D800, isnt it? I mean don't get me wrong I wouldn't buy one myself but I notice a ton of articles have really degenerated into that lately.

Feb 03, 2013 at 06:21 AM

alundeb
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p.2 #18 · “Full Frame Equivalence” and Why It Doesn’t Matter

mpmendenhall wrote:
I'm pretty sure "f-stop" is even more arcane. Entrance pupil size is one of the most obvious and easy to understand concepts about a lens: it's how big the hole in front is that light goes in --- unlike f-stop and focal length, you can actually see how big the light-hole is just by looking at the lens. And bigger = more light (unlike f-stop, where you have to figure out that small numbers are "better" by the inverse square). And it makes depth-of-field (in object space) easier to visualize by the light cone coming from the entrance pupil (instead of expecting folks to grok circles of confusion in microns on the image plane).

+1

Feb 03, 2013 at 08:03 AM

pdmphoto
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p.2 #19 · “Full Frame Equivalence” and Why It Doesn’t Matter

I've shot 4x5 to 645, 35mm, APS-C and most of the smaller formats. While "full frame equivalence" is a nice term, it is just that - based on the math. I don't find it holds up well in real world terms with digital sensors. There is a reason I still hold onto my 5DII and large lenses. Sure I can get the same equivalent result with another format, but it doesn't give me the same quality results across the board.

There are some areas where it is more apparent than others. Fast lenses wide open is one. I have the Canon 85/1.2 and 85/1.8 for my 5DII. Shooting a 50/1.2 or 50/1.4 on APS-C just doesn't give me the same result (at equivalent aperture), as the 85's on FF. I see the same comparing fast 50's on FF to 35's on APS-C. Landscapes with wides also seem to suffer on smaller formats. Part of this may have to do with the smaller format lenses having different characteristics across the frame (especially in relation to the pixel size/location), and then there is diffraction which happens sooner with smaller sensors. You can say you don't have to stop down as much to get the same DOF, but something seems lacking. I tried a 7-14 on 4/3rd's, and while it was a nice lens technically, it lacked the character I see on FF sensors at equivalent focal/aperture settings.

Feb 03, 2013 at 08:22 AM

alundeb
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p.2 #20 · “Full Frame Equivalence” and Why It Doesn’t Matter

Jman13 wrote:
The article wasn't written for FMers...you guys know this stuff.

Thanks for that clarification! I thought the remarks about people going on about equivalence included some of us here. I should have remembered that if you write articles of interest to us, you share them here yourself.

About the rabiat fanboys, I can understand that some people feel provoked. Like when you say that a 35-100 mm f/2.8 lens is equivalent to a 70-200 mm f/2.8 except DOF. You know that this is not the case, not for shutter speed. IMO you are fuelling the attacks yourself by pretending the smaller format has advantages that are not real, even though you know better.

Feb 03, 2013 at 09:00 AM

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