Ad
Ad
Ad
Pages: « 1 [2] 3 »   Bottom of Page
Print
Author Topic: 4/3 vs APS-C sensor size  (Read 15771 times)
AlfSollund
Full Member
***
Offline Offline

Posts: 128


« Reply #20 on: June 21, 2012, 01:28:07 AM »
ReplyReply

Leaving the interesting DoF discussion aside (eheeem). Sorry if I sound double sarcastic, but one could state that about all digital camera's: "they're not all that different". I would say that a main difference of these two is their sensor size, and if you try your Canon lenses on both you will see the difference. If you cannot use your Canon lenses on both I would say that one argument is missing for choosing either one of these, and its up to yourself to decide if this matters.

Anyway, best of luck!
Logged

-------
- If your're not telling a story with photo you're only adding noise -
http://alfsollund.com/
Jim Pascoe
Sr. Member
****
Offline Offline

Posts: 743


WWW
« Reply #21 on: June 21, 2012, 04:50:41 AM »
ReplyReply

To return to the original post, I should think the real decision is going to rest on how you feel about using the cameras and how they handle.  In this comparison the IQ question is going to be less important.

Jim
Logged
AFairley
Sr. Member
****
Offline Offline

Posts: 1130



« Reply #22 on: June 21, 2012, 08:26:14 AM »
ReplyReply

G
Leaving the interesting DoF discussion aside (eheeem). Sorry if I sound double sarcastic, but one could state that about all digital camera's: "they're not all that different". I would say that a main difference of these two is their sensor size, and if you try your Canon lenses on both you will see the difference. If you cannot use your Canon lenses on both I would say that one argument is missing for choosing either one of these, and its up to yourself to decide if this matters.

Anyway, best of luck!

I suspect that the relative strengths of the AA filters and differences in sensor technology would outweigh the difference in size with current sensors.  No empirical basis to say, just saying it.
Logged

Ray
Sr. Member
****
Offline Offline

Posts: 8852


« Reply #23 on: June 21, 2012, 08:28:21 AM »
ReplyReply

No we don't. If we keep all variables (focal length, aperture and subject distance) constant, the larger the sensor the larger the DOF, but the framing changes too since the FOV is wider. If we adapt focal length and/or subject distance to match the framing (in case we modify subject distance, perspective also changes), the larger the sensor the shallower the DOF.

Hi Guillermo,

Scooby70 is partly correct when he writes:
Quote
We do know that sensor size as such does not affect DoF don't we? We do know that with smaller sensors you tend to use wider lenses and that's why you get more DoF?

If we keep all variables constant, such as focal length, aperture, and subject distance, the larger sensor will produce a larger field, a wider 'field of view' or wider FoV. In some situations, that larger field may have greater depth, and only then will the image exhibit greater DoF.

Consider the example of a photograph of the facade of a house in which the whole house fills the frame of the smaller sensor, using a fairly wide aperture so that not all parts of the house are equally sharp, like the ridge of the roof, which is furthest away and therefore a little soft.

Supposing we take the same shot with a camera with a larger sensor, using the same lens with the same settings. The DoF of the facade of the house will be approximately the same. The ridge of the roof will be equally soft in both shots, and all other parts of the facade will be equally sharp (depending on sensor pixel density).

What may be more blurred in the shot using the larger sensor are any parts of the scene outside of the FoV of the smaller sensor, which are further away, or closer to, the person taking the shot, such as background mountains, or the garden in front of the house. If there are no parts further away, or closer, in the wider shot, DoF will not be shallower.

In this sense, any apparent shallower DoF in the image from the larger sensor is not due to the sensor size as such, or per se, but is both scene and FoV dependent.

One has to ask here, is it sensible to talk about differences in DoF between different images? Is it meaningful?

Cheers!
Logged
Lightsmith
Full Member
***
Offline Offline

Posts: 111


« Reply #24 on: June 21, 2012, 10:11:22 PM »
ReplyReply

As a practical manner and currently owning APS-C, 4/3 mirrorless, and full frame DSLR cameras, the mirrorless have limitations which go beyond the size of the sensor. The 4/3 sensor is 6x as large as that on most P&S cameras and is good up to ISO 1600 so it should not be discounted out of hand.

The problems I see related to the lack of a viewfinder which results in two problems, one being the inability to quickly select a point of focus, and the second being the inability to brace the camera and instead having to hold it out from the body to view the LCD display on the back. I need 2x the shutter speed with the same FOV with any mirrorless camera compared to a standard DSLR with a viewfinder.

For photographing whales from the deck of a boat or birds in flight the mirrorless is a poor choice. For photographing hand held in low light the mirrorless camera is a poor choice. But that leaves open many situations, especially with the addition of flash where the mirrorless cameras are quite good.

I bought a 4/3 mirrorless Olympus E-PL1 for my wife and it has a flash that pops up and extends away from the camera for good fill flash and it has the ability to remotely provide TTL control over a remote Olympus or Metz flash which is a huge advantage compared to most non Canon or Nikon cameras. I have used this same feature to good advantage with my D200/D300/D800E cameras and with the SU-800 on my D3.

I read too many posts where people find themselves physically unable to carry around more than one lens with their DSLR and want advice on which ONE lens they should choose. They would be better off in many cases with a 4/3 camera and a zoom lens - the E-PL1 with its battery and 28-84mm FOV equivalent zoom weighs a total of 17 ounces or less than most of my Nikon lenses by themselves.
Logged
AFairley
Sr. Member
****
Offline Offline

Posts: 1130



« Reply #25 on: June 22, 2012, 12:15:12 PM »
ReplyReply

The problems I see related to the lack of a viewfinder which results in two problems, one being the inability to quickly select a point of focus, and the second being the inability to brace the camera and instead having to hold it out from the body to view the LCD display on the back. I need 2x the shutter speed with the same FOV with any mirrorless camera compared to a standard DSLR with a viewfinder.

Of course, this is not an issue with the Olympus E-M5 or the Pansonic GH-x series, all of which have built-in EVFs.
Logged

k bennett
Sr. Member
****
Offline Offline

Posts: 1417


WWW
« Reply #26 on: June 22, 2012, 12:39:00 PM »
ReplyReply

Or the very first m4/3 camera, the Panasonic G1, which my wife still uses very happily. The G2 and G3 follow the same form with an excellent built-in EVF, as does my GH2. And of course an accessory EVF is available for many other m4/3 cameras. I would consider it a mandatory purchase.
Logged

Equipment: a camera and some lenses.
John Camp
Sr. Member
****
Offline Offline

Posts: 1258


« Reply #27 on: June 22, 2012, 01:10:59 PM »
ReplyReply

In his review of the OMD, Michael says it's good up to ISO 3200, and is very comparable to the NEX's APS-C sensor.

The D3 was, three years ago, considered a brilliant low-light camera, and I would not routinely push that past ISO 3200. I have two GX1s with the optional viewfinders and consider them the best street cameras I've ever used. 
Logged
scooby70
Full Member
***
Offline Offline

Posts: 211


« Reply #28 on: June 22, 2012, 02:50:48 PM »
ReplyReply

Hi Guillermo,

Scooby70 is partly correct when he writes: ...

Talking about DoF is one of the most contentious issues Cheesy

In the past I've taken the same shot from the same spot with two different cameras with very similar lenses set to the same aperture. To make life easy a 5D and MFT (Micro Four Thirds, x2 crop) were good to compare. What I got was two images with different fields of view, as expected, and if I ignored or cropped out the image elements in the 5D shot which were not present in the MFT shot what I got was two images which in pretty much all real world ways were identical, and this didn't surprise me. There will be differences if we look closely enough as they're captured by very similar but not identical lenses and different chips but essentially the images were the same.

Given two sensors of identical design but different size there should be no difference at all between a whole and a cropped image. I believe that some DSLR's have a "crop" shooting mode so anyone lucky enough to own one should be able to test this theory.

Magnification, viewing distance and circles of confusion often get spoken about in discussions about DoF but it's best to concentrate on aperture, focal length and camera to subject distance unless going to extremes, IMVHO.

So, what works for me personally is believe that sensor size has no (real world) effect on DoF, not in the way that aperture, zoom length and camera to subject distance do as that's what my own logic and own tests show me. Anyone else is free to take and compare their own images and that's easy these days as many of us now own cameras with different sized sensors. Once shots have been taken and compared we are all free to make our own minds up about what affects DoF Cheesy It's just that in my own mind, saying that cropping a image alters the DoF makes no sense at all Cheesy
Logged
scooby70
Full Member
***
Offline Offline

Posts: 211


« Reply #29 on: June 22, 2012, 02:52:32 PM »
ReplyReply

One has to ask here, is it sensible to talk about differences in DoF between different images? Is it meaningful?

Only as a mental exercise or when wanting to start a fight in an empty room Cheesy
Logged
PeterAit
Sr. Member
****
Offline Offline

Posts: 1786



WWW
« Reply #30 on: June 22, 2012, 05:25:52 PM »
ReplyReply

No no no, this is not true. The sensor size has no effect on DOF except thru the requirement for wider lenses for smaller sensors.

Think about it. Take a 4x5 view camera with a certain lens at a specified aperture. The image on the ground glass will have a certain depth of field. Now put a rectangular mask over the ground glass so that you can see only the middle 2x3 inch area - the equivalent of a smaller sensor - and change nothing else. Do you really think the DOF will change? Duh, no!
Logged

Peter
"Photographic technique is a means to an end, never the end itself."
View my photos at http://www.peteraitken.com
Ray
Sr. Member
****
Offline Offline

Posts: 8852


« Reply #31 on: June 22, 2012, 08:53:36 PM »
ReplyReply

No no no, this is not true. The sensor size has no effect on DOF except thru the requirement for wider lenses for smaller sensors.

Think about it. Take a 4x5 view camera with a certain lens at a specified aperture. The image on the ground glass will have a certain depth of field. Now put a rectangular mask over the ground glass so that you can see only the middle 2x3 inch area - the equivalent of a smaller sensor - and change nothing else. Do you really think the DOF will change? Duh, no!

One has to ask here, 'The DoF of what?' The DoF of the uncropped scene, or the DoF of the cropped scene?

The reason why I can't completely disagree with Guillermo, is because Depth of Field is fundamentally a property of a field that has an illusion of depth on a two-dimensional representation.

Sometimes a change in the extent and size of the field, through cropping, will also result in a change in the depth of that field (ie. the fuzzy bits are cropped out). However, sometimes there may be no fuzzy bits, or fuzzier bits in the wider shot. Using the larger sensor we may simply get a wider shot of the facade of a large house, showing more windows and awnings.

To make this point clearer for the benefit of those who are logically challenged, we should go back to the basic definition of DoF. The defintion I'm using in this post is as follows. "Depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image." This is also the definition that Wikipedia uses.

A major point in this definition, is that DoF is essentially a property of a scene. If one changes the scene (through cropping) then clearly the possibility of changing the DoF must exist, but it's not inevitable or unavoidable. It depends on the scene. This is why I maintain that a change in sensor size, keeping everything else the same, will not always result in a change in DoF, but sometimes it will. Therefore both Guillermo and Scooby 70 are partially correct, but neither is completely correct.

For the benefit of those who are new to such concepts, all cameras in reality are cropped-format cameras. The difference is only in the degree of cropping. The image circle projected by the lens is always cropped. If it weren't, you'd have a circular image with a very dark and degraded circumference. Whether the scene is cropped by the sensor, or cropped in post-processing, makes no difference if the resulting FoV is the same.
Logged
Guillermo Luijk
Sr. Member
****
Offline Offline

Posts: 1274



WWW
« Reply #32 on: June 23, 2012, 02:21:37 PM »
ReplyReply

It's just that in my own mind, saying that cropping a image alters the DoF makes no sense at all Cheesy

It makes sense when you apply the definition of DOF: area (distance) in front of and behind the focused subject, that still seems to be in focus to our eyes for a given angle of observation of the image. If you use a cropped image, you could be able to distinguish blurred elements that appeared to be in focus in the non-cropped image, just because in the cropped version you are observing them with a higher magnification.

For the same reason and according to the definition, DOF changes with the viewing distance to a printed image. An image that may look to be entirely in focus to your eyes when observed from let's say 10m, could reveal out of focus elements as you get closer to the print.

People stating that DOF doesn't get altered with format, just don't understand the definition of DOF.

Regards
« Last Edit: June 23, 2012, 02:26:49 PM by Guillermo Luijk » Logged

Ray
Sr. Member
****
Offline Offline

Posts: 8852


« Reply #33 on: June 23, 2012, 08:45:44 PM »
ReplyReply

It makes sense when you apply the definition of DOF: area (distance) in front of and behind the focused subject, that still seems to be in focus to our eyes for a given angle of observation of the image. If you use a cropped image, you could be able to distinguish blurred elements that appeared to be in focus in the non-cropped image, just because in the cropped version you are observing them with a higher magnification.

For the same reason and according to the definition, DOF changes with the viewing distance to a printed image. An image that may look to be entirely in focus to your eyes when observed from let's say 10m, could reveal out of focus elements as you get closer to the print.

People stating that DOF doesn't get altered with format, just don't understand the definition of DOF.

Regards


On the other hand, Guillermo, if we keep all variables constant, which is the condition you stated in an earlier post, then these changes in viewing distance should not apply.

When isolating a specific quality for comparison, such as DoF and how it may change with sensor size, one should try to keep all other variables constant if possible. If you wish to compare how DoF changes with viewing distance from a print, then that should be a separate experiment in which one should keep not only sensor size, print size, and lens settings constant, but actually use the same camera and lens.

However, there are certain situations when it may not be possible to keep all other variables constant, as is the case when comparing images taken with different size sensors using the same lens, with same settings, from the same position.

If one crops the image from the larger sensor to the same size and aspect ratio of the image from the smaller sensor, then one is effectively comparing equal size sensors. Not much point in that, unless one is comparing some other quality such as the effect on resolution from the different pixel densities of the two sensors, as in a comparison between the Canon 7D and the 5D3.

In order to compare the effect that the larger sensor has on the DoF of a scene, one cannot sensibly crop the scene from the larger sensor in post-processing, because that would constitute a discarding of image information, and scene information, from the larger sensor. That would be really unscientific. However one should at least try to keep other variables constant, such as lens, aperture, focal length, shooting position, and print viewing distance.

But what about print size? Here we have a dilemma. If the two different size sensors happen to have the same pixel count and the same aspect ratio, we can also achieve equal print size without discarding any image information from one of the sensors and without applying unequal interpolation to the images for printing purposes.

Whilst there certainly are cameras with different size sensors but similar or identical pixel counts, such as the Canon 1Ds2 and the Nikon D7000, the larger sensor usually has more pixels, so for the sake of clarity on this issue I'd make the following summary.

When comparing the DoF of two different sized sensors, it's not possible to keep all variables constant. The options are:

(1) Keep everything constant except FoV, and print size in circumstances when the two sensors have a different pixel count.

(2) Keep FoV constant by changing focal length of lens used, with the same problem applying to print size in accordance with pixel count.

Take your pick. Grin In both situations there is at least one additional variable which cannot be constant, apart from the obvious variable of sensor size which is a necessary variable and the basis of the comparison.
Logged
Guillermo Luijk
Sr. Member
****
Offline Offline

Posts: 1274



WWW
« Reply #34 on: June 24, 2012, 03:26:45 AM »
ReplyReply

When comparing the DoF of two different sized sensors, it's not possible to keep all variables constant. The options are:

(1) Keep everything constant except FoV

Ray, FOV is not an independent variable, it's a resulting variable of sensor size and focal length. Hence it cannot be preserved if sensor size changes and focal length remains. The point is that sensor size itself (i.e. if you voluntarily only change sensor size/cropping and don't touch anything else) affects DOF. And it also affects FOV, since FOV is another output variable.

I think it is not worth taking the discussion furhter because it has become purely semantic/philosophycal and I think we all agree in what's going on.
« Last Edit: June 24, 2012, 03:30:23 AM by Guillermo Luijk » Logged

Ray
Sr. Member
****
Offline Offline

Posts: 8852


« Reply #35 on: June 24, 2012, 04:10:39 AM »
ReplyReply

I think it is not worth taking the discussion furhter because it has become purely semantic/philosophycal and I think we all agree in what's going on.

Good! I thought I sensed some disagreement on the issue in previous threads, which is why I contributed my opinion in the hope of dispelling some confusion.  Grin
Logged
AFairley
Sr. Member
****
Offline Offline

Posts: 1130



« Reply #36 on: June 24, 2012, 11:19:52 AM »
ReplyReply



I think it is not worth taking the discussion furhter because it has become purely semantic/philosophycal and I think we all agree in what's going on.


Not to mention that the thread has been totally hijacked
Logged

Ray
Sr. Member
****
Offline Offline

Posts: 8852


« Reply #37 on: June 24, 2012, 06:52:23 PM »
ReplyReply

Not to mention that the thread has been totally hijacked

By whom? All my comments are directly related to the effects and consequences of differences in sensor size. Isn't this the subject of the thread, the impact of the different sensor sizes of 4/3rds format and APS-C format?
Logged
elf
Full Member
***
Offline Offline

Posts: 229


« Reply #38 on: June 25, 2012, 01:52:50 AM »
ReplyReply

You can stitch or crop images taken with the same lens, aperture, and perspective(same physical location of lens and subject) from different sensors and easily demonstrate the DOF is identical.  What's harder to determine theoretically is what the IQ of each will be.

In any case, pretty much any current camera will take excellent pictures in normal conditions. I'd say base your purchase on ergonomics first, lens availability second, and subject type (low light, portrait, sports, etc.) last.

p.s. Just get the D800 and don't worry about any of the above Smiley
Logged
Thomas Krüger
Sr. Member
****
Offline Offline

Posts: 451



WWW
« Reply #39 on: June 25, 2012, 02:16:35 AM »
ReplyReply

p.s. Just get the D800 and don't worry about any of the above Smiley

...and if you get a D800 add also a D3200 as a second body. Just a little bit larger as the MFT Panasonic G3 - to come back to the 4/3 vs APS-C sensor size discussion. 
Logged
Pages: « 1 [2] 3 »   Top of Page
Print
Jump to:  

Ad
Ad
Ad