Crop vs FF for landscape photography

[phixional ninja]

Zooming changes the focal length being used which changes the FoV. But as long as the distance between the camera and subject are not changed, perspective is preserved. What this basically means is that you're effectively cutting out the outer areas of the image. The perspective change comes when you try to move the camera closer or farther away from the subject.

Perhaps I'm not doing a good job of it, but I'm talking about this. That example is moving the camera to preserve the size of the subject, but that's because it's dealing with a single camera and sensor size. In my hypothetical though, a full frame and a crop camera in the same position would require different focal lengths to capture equivalent fields of view (as described by Neuro). (Again, as I understand it) The longer focal length on the full frame camera would offer greater distance compression though, and so a shot with a far away mountain would appear to bring that mountain closer.

Edit to add:

As some people would say in these forums, if you don't really plan on printing your pictures and resolution is not that critical, you can crop a FF image in post. Since there isn't any perspective difference, you can get the APS-C reach by cropping an 8.64MP out of a 22.1MP image. That might sound like a big loss but that's still a good 3600x2400 image! For screen use, only a few displays can even match that kind resolution and that's certainly not the general public!

To clarify, I am not bemoaning the lesser apparent reach of full frame. My hypothetical assumes available glass to get the same field of view on both sensors without cropping. I'm less concerned with the overall size the mountain takes up in the frame (solvable with cropping), and more with its relative size compared to everything else (which cropping doesn't change).

 

[nightsky87]

Perhaps I'm not doing a good job of it, but I'm talking about this. That example is moving the camera to preserve the size of the subject, but that's because it's dealing with a single camera and sensor size. In my hypothetical though, a full frame and a crop camera in the same position would require different focal lengths to capture equivalent fields of view (as described by Neuro). (Again, as I understand it) The longer focal length on the full frame camera would offer greater distance compression though, and so a shot with a far away mountain would appear to bring that mountain closer.

In that particular example, the camera was moved around as you mentioned. Focal length doesn't inherently change the perspective. Its the camera-subject distance that does this. So increasing focal length means your subject is larger. To maintain the same subject size, you step back which then changes perspective.

In the APS-C and FF discussion, the FF has a wider FoV due to the bigger sensor. So to get the same FoV as the crop sensor, you can zoom in (increase focal length) without moving the camera. No camera movement = same perspective and same compression.

To clarify, I am not bemoaning the lesser apparent reach of full frame. My hypothetical assumes available glass to get the same field of view on both sensors without cropping. I'm less concerned with the overall size the mountain takes up in the frame (solvable with cropping), and more with its relative size compared to everything else (which cropping doesn't change).

Undeniably, there will be differences in FF and APS-C if you try to maintain the same subject sizing with the same focal length. But assuming you're simply using the zoom of the lens, there will be no difference in relative sizing. So if what you're saying is that you have a lens and use it with the same focal length for both sensors, you have to move to maintain the FoV which then changes perspective.

 

[phixional ninja]

Perhaps I'm not doing a good job of it, but I'm talking about this. That example is moving the camera to preserve the size of the subject, but that's because it's dealing with a single camera and sensor size. In my hypothetical though, a full frame and a crop camera in the same position would require different focal lengths to capture equivalent fields of view (as described by Neuro). (Again, as I understand it) The longer focal length on the full frame camera would offer greater distance compression though, and so a shot with a far away mountain would appear to bring that mountain closer.

In that particular example, the camera was moved around as you mentioned. Focal length doesn't inherently change the perspective. Its the camera-subject distance that does this. So increasing focal length means your subject is larger. To maintain the same subject size, you step back which then changes perspective.

In the APS-C and FF discussion, the FF has a wider FoV due to the bigger sensor. So to get the same FoV as the crop sensor, you can zoom in (increase focal length) without moving the camera. No camera movement = same perspective and same compression.

Well dang, it looks like you are totally right: http://www.scottbideauphotography.com/myths-about-lens-compression/

I've always heard it referred to as "lens compression" and read stuff like this which make it sound as though the focal length is what is responsible for the phenomenon. Nope!

Thanks for prodding me into reading further.

 

[nightsky87]

Perhaps I'm not doing a good job of it, but I'm talking about this. That example is moving the camera to preserve the size of the subject, but that's because it's dealing with a single camera and sensor size. In my hypothetical though, a full frame and a crop camera in the same position would require different focal lengths to capture equivalent fields of view (as described by Neuro). (Again, as I understand it) The longer focal length on the full frame camera would offer greater distance compression though, and so a shot with a far away mountain would appear to bring that mountain closer.

In that particular example, the camera was moved around as you mentioned. Focal length doesn't inherently change the perspective. Its the camera-subject distance that does this. So increasing focal length means your subject is larger. To maintain the same subject size, you step back which then changes perspective.

In the APS-C and FF discussion, the FF has a wider FoV due to the bigger sensor. So to get the same FoV as the crop sensor, you can zoom in (increase focal length) without moving the camera. No camera movement = same perspective and same compression.

Well dang, it looks like you are totally right: http://www.scottbideauphotography.com/myths-about-lens-compression/

I've always heard it referred to as "lens compression" and read stuff like this which make it sound as though the focal length is what is responsible for the phenomenon. Nope!

Thanks for prodding me into reading further.

You're welcome. I actually used to think the same way myself. When I read about how focal length doesn't actually change perspective (I think it was some post by neuro), I went out to my balcony to confirm it.

 

[Loswr]

Zooming changes the focal length being used which changes the FoV. But as long as the distance between the camera and subject are not changed, perspective is preserved. What this basically means is that you're effectively cutting out the outer areas of the image. The perspective change comes when you try to move the camera closer or farther away from the subject.

Perhaps I'm not doing a good job of it, but I'm talking about this. That example is moving the camera to preserve the size of the subject, but that's because it's dealing with a single camera and sensor size. In my hypothetical though, a full frame and a crop camera in the same position would require different focal lengths to capture equivalent fields of view (as described by Neuro). (Again, as I understand it) The longer focal length on the full frame camera would offer greater distance compression though, and so a shot with a far away mountain would appear to bring that mountain closer.

Just to drive the point home, I pulled this from a recent post of mine on this issue.


Here's an example from the wiki page on perspective distortion, an example that illustrates some of this confusion:

You see the different focal lengths printed on the images, and you see the relative sizes of the two water bottles changing, and you think that focal length is the reason. Even the text in the caption of that image suggests the effect is due to focal length. But consider...the pink bottle is the same height in all three images - therefore, as the focal length is reduced, the camera must have been moved closer to achieve the same framing. It's the movement of the camera, not the change in focal length, that results in the different perspectives.

Let me try to illustrate what I mean with a similar set of examples, but where I first vary just focal length but not distance, and then vary focal length and distance. Since I prefer beverages other than water, I selected a different pair of subjects for a similar test.

The two bottles are 18" apart, and the distances in the image are measured from the sensor to the front bottle. All were shot at f/5.6. As described above, it's normal for the bottle in front to look larger, that's perspective - objects that are further away look smaller, even though we know they are the same size. Note that the bottle in front is the same height in all the images.

In the left column, the 50mm and 24mm shots were at the same distance as the 100mm images, and the images were cropped to match the framing of the 100mm image. As you can see, the relative size of the rear bottle is the same in all the images. The perspective is the same - the two bottles maintain the same relative size, despite the differing focal lengths. The distance is the same, so the perspective is the same.

In the right column, which is equivalent to the water bottle shots from the wiki page, the 50mm and 24mm shots were taken at successively closer distances to the bottles, matching the framing to the 100mm shot by moving the camera. As you can see, the relative size of the rear bottle gets smaller as the camera is moved closer. Different perspective, because the distance is changing. Comparing the side-by-side 50mm and 24mm images, you can see that with the same focal length but different subject distances, the perspective is different.

So, varying focal length alone, without changing distance, does not affect perspective. As stated above (by me and others), perspective is determined by distance, and distance alone.

'Telephoto' compression and 'wide angle' expansion distortion are the same phenomenon. The reference to 'telephoto' and 'wide angle' there is misleading - it has nothing to do with the focal lengths, only the distance. But longer lenses are usually used at longer distances, and wide lenses are usually used at closer distances (think of framing a person for a portrait), thus the erroneous association with a lens type when it's really the commonly used distances for those lenses that is the cause of both types of perspective distortion.


Ps. the Chocolate Stout was very good.

 

[Anthony]

With my 7D, I can do 18 Mpix to Gpix.
What else. If you want high resolution, slice your scenery into small parts and shoot. Then use pano tools.

http://www.kolor.com/panogear-motorized-panoramic-head.html

 

[Area256]

So I was wondering, if higher pixel density is useful for landscape photos, would the 7D be a more useful tool for the job than say the 5Ds or 6D. As I understand it (which may not be very well...) the shallower DOF with FF is no advantage and neither is high ISO capabilities if shooting with good ambient light (which most landscape shots tend to have I think).

I ask because i want to take more landscape shots. I currently own a 40D and am thinking of getting a 10-22mm. However, i will prob upgrade from the 40D in the new year (once we know what's happening with the 7D line) and may move to full frame (which would make the 10-22 redundant).

My first post btw - thanks all

think like this, a smaller sensor requires more of the lenses, about 1.5 (nikon aps) better resolution and contrast, so it is always better with a larger sensor if everything is equal when it comes to the actual sensor design and resolution.
example 20mp and 24x36 surface and 20 mp at a APS surface.
Is it landscape, details the larger sensor is always better and you must compensate the reach with longer lenses

+1 With my 6D most of my lenses visibly resolve much more detail, despite only having 2 more MP than the 60D. With very high quality optics, like the 100mm f/2.8L, it's harder to see the difference in detail/sharpness.

However, there are three advantages that even the best optics won't give you on crop, and that is DR, tonal range, and color depth. Since the surface area is larger on a FF, it takes more light per pixel (or down-sampled pixel on a D800), and thus can read smaller changes in colour and brightness, and pick up smaller details in darker parts of the frame (giving more DR in post).

You'll almost always be shooting at ISO 100, and you may need to stop down more to get enough DOF, but since you can just expose for longer, a FF will collect more light per (resolution adjusted) pixel. So you will have better DR, tonal range, and color depth than on a crop sensor camera. There seems to be a war going on about whether a person can actually notice that, and I won't get into that, but there are at least technical reasons that FF is much better than crop for landscape photography. Note some crop sensors can, due to better design, do just as well as some lesser quality FF sensor on these metrics. So sensor design clearly has an impact, but sensor design aside, the FF will do better between two sensors of the same design. Also it's fair to say Nikon (via Sony) has the edge at the moment in sensor design, but I own a 6D, not a d600, so sensors aren't everything.

 

[AudioGlenn]

so to sum it all up, the majority of responses vote for "FF for landscape photography". You can use the APS-C sensor with a 10-22 if you'd like but it might take a little extra work in post.

I just went full frame so I'm still a noob. What I can say is that I notice qualities in my photos from the 5D mkiii that I NEVER noticed from my 60D. It was as if I could "feel" textures in the photos... and that's with the same lenses. I'm saving for a 16-35 2.8 II to complete my 2.8 zoom trinity. For now, 24mm is wide enough for some casual landscape shots. I have the 60D and 10-22mm on hand until I can sell it to put more money towards the new 16-35...or hopefully a 14-24 2.8L.

As far as opinions go, I think neuro does a great job of helping others (on CR) out with real world experience and accurate data. I've done my share of reading too much into what's written on the forums and getting offended when I didn't need to be. Let's all just enjoy the holidays and post up some great Winter Landscape pictures! I hear winter time is great for that style of photography =)