There have been some interesting discussions about the pros and cons of various sensor sizes and how they impact angle of view, lens focal length and the depth-of-field that results. For example, some photographers bemoan the fact that it is difficult to achieve a shallow depth of field at a particular equivalent-field-of-view with a CX sensor using 1 Nikon lenses, while others find it useful to be able to get deeper depth-of-field at more open aperture settings such as f/1.8 and f/2. Some D800 shooters are concerned about diffraction setting in above f/8 when trying to achieve deep depth-of-field with a high pixel density 36mp FX sensor, as are many photographers who use high pixel density sensor DX bodies.
At the end of the day there is no such thing as a perfect camera body or format that will suit everyone’s needs. The camera body and sensor format you choose, along with your choice of lenses,comes down to the creative requirements that you have as a photographer based on the work you do.
While the size of a camera’s sensor does not directly affect depth-of-field, the sensor size does impact field of view….smaller sensors have narrower fields of view. So, to achieve a particular angle-of-view the focal length of the lens on a CX body will need to be wider when compared to a full frame camera body at that same desired angle-of-view.
This can be confusing, so let’s consider a 50mm full frame lens mounted on a full frame camera like a D800. That lens has an angle of view of 47-degrees on a D800. To get an equivalent angle of view with a Nikon 1 V2 using a 1 Nikon lens you would need to use a 1 Nikon 18.5mm lens. That lens has an angle of view of about 46.4degrees on a CX body…so almost identical to the 50mm FX on an FX body.
The key thing to remember when shooting with a Nikon 1 V2 with the 18.5mm lens is that we are, in fact, shooting with a wide angle lens so we are getting the depth of field characteristics associated with a lens with a focal length of 18.5mm. So, while we are getting an angle of view similar to shooting with a 50mm FX lens on an FX body…we are also getting much different depth-of-field characteristics since we are actually shooting with an 18.5mm wide angle lens to get the desired angle of view on a CX body with its smaller sensor. That will give us more depth-of-field at any given f-stop on a CX body than a 50mm FX lens does on an FX body at that same f-stop.
As many of you know from an earlier posting of mine, I am now a dedicated FX/CX shooter, having sold all of my DX gear. I do a lot of video work for clients and I find a combination of FX/CX works best for the work I do.
In order to demonstrate how FX and CX sensors can affect angle of view, lens focal length and the related depth-of-fieldI staged a small experiment, placing three boxes exactly 12-inches apart from each other so that the cover of the first box was 24” in front of the cover of the box in the background. The cover of the middle box was exactly 12-inches from the covers of the other two boxes.
I then shot a series of exposures with a Nikon 1 V2 using the 1 Nikkor 18.5 f/1.8 lens, which has an equivalent field-of-view of 50mm when compared to an FX lens. Then, I used my Nikon D800 along with a Nikon 1 V2 with the FT-1 adapter and shot the three boxes using the Nikkor 50mm f/1.8G lens. With the 2.7X crop factor of the Nikon 1 V2, the 50mm has an equivalent field-of-view of 135mm when used with the V2.
On the FX side, I used the Nikon D800 with the . In order to try and demonstrate the creative potential of these three different set-ups, I tried to fill the frame with the box in the foreground in all of the images. Here is the result:
The outcome is pretty clear and expected – with the same equivalent field of view, CX produces more depth of field than FX.
Next, I compared both at f/5.6:
Once again, the difference in depth of field is quite noticeable.
Lastly, I used my Nikon 1 V2 with the FT-1 adapter and shot the three boxes using the Nikkor 50mm f/1.8G lens. With the 2.7X crop factor of the Nikon 1 V2, the 50mm has an equivalent field-of-view of 135mm when used with the V2:
The above shows three very different outcomes: FX generated shallow depth-of-field images, CX created deep depth-of-field images, and CX when used with the FT-1 created compressed depth-of-field images.
In my view, none of these types of images is any better or worse than the others. They are simply different creative options that are available depending on the needs of a specific photographer / videographer working to fulfill the requirements of a specific assignment.
How do depth-of-filed considerations affect your choice of camera gear? What format(s) do you currently use and why? Are you considering any kind of format change? If so, what are you thinking of doing and why?
Article and all images Copyright 2014, Thomas Stirr. All rights reserved. No use, reproduction or duplication including electronic is allowed without written consent.
Very interesting analysis!
I’m glad you found the article useful.
Good article to let us think more when photographing and choosing gears …
Trying to answer (myself first) your questions, I believe fundamental to choose what lens, what camera to prefer,
1) How do depth-of-filed considerations affect your choice of camera gear?
it’s not a strict issue for my kind of shooting; I’ve only a 50mm f/1.8 G Nikon I bought to make shallow dof shots.
2) What format(s) do you currently use and why?
I use Dx, but have used film cameras (that are Fx ;) for some years.
Dx was the only choice when I switched from SLR to DSLR, the Fx camera was a little expensive to buy for me, since I’m only an enthusiast.
Now the weight is a criterion I’ve added to decive how to evolve … Fx cameras are better, but heavier to carry when travelling :(
3) Are you considering any kind of format change?
I haven’t planned a change in months, but if I seriously had to decide I’d try the Dx mirrorrless systems, like Fuji X. These lenses should give the same dof of a Dx DSLR, right? The only three “issues” for such a change would be a) I’ll have to change all my lenses – so lots of money – b) abandoning then the DSLR system. Why to keep both my Dx camera and a Dx mirrorless? c) most of all, may be, the ISO performance. But my Dx camera is a Nikon d300; don’t think so better than the best Fuji X currently in the market
4) If so, what are you thinking of doing and why?
despite my answer to the previous question what I really say is .. “:S” .. d0n’t know …
I use my camera as a “travel mate” or for shooting sessions when I’ve time or no such issues to carry lenses so … don’t know …
Thanks for sharing your thoughts on the gear you are currently using and what you may consider in the future. Interesting to hear that weight is becoming a purchase factor for you….that is something that more and more people are putting on their list of criterion. It’s also interesting that you mention the Fuji X series of cameras…..more and more people seem to saying very positive things about Fuji.
Nasim wrote an in-depth review of the Fuji X-E2 in December 2013 and gave it very high scores:
All of us struggle with the total cost associated with making a format change when it comes to body and lenses….it is a big decision to make!
I wonder if any Photography Life readers have made the switch from a Nikon D300 or D300s to Fuji and how they feel about making the change. Maybe we’ll get some reader comments in this regard.
Hi Tom, thank you too!
Would be nice to know if someone who has made such a change (from the “tank” D300 – great AF, lots of customization due to banks, great ISO performance in last years, when it was most preferred by sport and action photographes, and still the possibility to use non AF lenses) to a more modern, light and “LCD dependent approach” camera is “suffering” in a way, or desidering to switch back to DSLR, i.e. to Fx.
Many Fuji X but the top don’t have a viewfinder and for many of us this could be is an issue …
For example, I’m not able to do the same I do with reflex whenviewing a display despite looking at the world arould me through a viewfinder …. I feel it differently .. the viewfinder is my eye, the LCD like a small tv set … all the around is not “all black” and, in a way, I get distracted …
Being a long time SLR shooter….and now DSLR…I am also very oriented to using a viewfinder. That’s one of the reasons that I have the V Series of Nikon 1 cameras in my kit. When I’m doing video projects for clients I find it easier to use the screen on the back of the camera and that feels somehow ‘natural’….but for shooting stills….I still need a viewfinder.
Josef James has an excellent article on this subject here: www.josephjamesphotography.com/equivalence/. He calculates how two different format cameras can be configured to produce identical images. This provides a useful reference point for comparing them. Your D800 can be configured to take pictures that look the same as your V2. Same angle of view, depth of field and (if the level of sensor technologies are about the same) noise and dynamic range. Pixels are pixels though, you’d have to down sample the D800 image to be the same megapixels as the V2.
A CX camera shooting with the 18.5 mm lens at f/1.8 and ISO100 is equivalent to an FX camera with a 50mm lens at f4.9 and ISO742. Both cameras would have the same shutter speed.
These values are calculated with the focal multiplier based on the ratio of the sensors diagonal dimensions, CX to FX is 2.7. 18.5 * 2.7 makes 50mm, this gives them same angle of view. Similarly, f/1.8 times 2.7 gives f/4.9 producing the the same depth of field. Since we’ve changed the exposure by increasing the f-ratio on the FX camera, increase it’s ISO to compensate. The multiplier for that is based on the ratio of FX vs CX sensor surface areas, that’s about 7.42 in this case. 7.42 times ISO100 = ISO 742. Setting the FX camera to that ISO will make the noise and dynamic range about the same. This can’t be exact because the sensor technologies are different.
This illustrates how larger sensors are superior to smaller ones. While the CX camera at it’s best, say the new 32mm f/1.2 at ISO100, is easily matched by the FX sensor camera with a 85mm lens at f/3.2 and ISO742. Of course, the FX camera can use wider apertures and slower ISO speeds, it can go places the CX camera can’t.
A handy rule of thumb is to think about the differences between formats by f-stops. Each of the common sensor formats are separated by about one f-stop FX to DX to m4/3rds to CX to 1/1.7 inch (like the P7800 et al). So a Nikon P7800 at ISO100 is equivalent to; CX at ISO200, m4/3rds at ISO400, DX at ISO800 and FX at ISO1600.
Some one else posted about Ansel Adam’s shooting at f/64. The depth of field for an 8×10 view camera at f/64 is equivalent to an FX sensor at f/8.
Thanks very much for your posting. We are certainly getting some good discussion and additional perspectives on this topic!
Nasim wrote an excellent piece about this subject: photographylife.com/equiv…ld-of-view
One of the issues that I was trying to address with my article (and one that I no doubt could have expressed with more clarity) was the creative challenge posed when shutter speed cannot be changed and ISO choices are limited…..but we still want to change aperture to achieve more depth-of-field. This situation is faced more commonly by video shooters than by still photographers.
To get natural looking motion in video when shooting with a DSLR or ILC it is important to match video frame rate and shutter speed. For example, when shooting at 30p a 1/60th shutter speed is typically used. In addition, video shooters are often limited in their choice of ISO due to the amount of noise in video clips. Most of the industrial productions I do are shot at a maximum of ISO-800. On very rare occasions I may shoot a clip at ISO-1600…but that’s the high end of how I shoot.
Let’s say I’m shooting video with my D800 and ideally I need to capture a scene using my 50mm f/1.8 G at f/8 to get the right framing and depth-of-field…but the lighting conditions will only allow me to shoot that lens at f/2.8. My shutter speed is locked in at 1/60th because I’m shooting at 30p and there is significant motion in the scene… and I’m already at my max ISO of 800. Even if I bump my ISO one stop to 1600 and change my aperture one stop to f/4 I still won’t have sufficient depth-of-field for the scene. Since I’m an FX/CX shooter the solution is simple…I change to my Nikon 1 V2 and shoot with my 1 Nikon 18.5mm f/1.8 @ f/2.8 at ISO-800 or f/4 at ISO-1600….and I’ll get the framing and depth-of-field I need for the scene.
For anyone interested in seeing a comparison of video performance between the D800 and the Nikon 1 V2 at various ISOs here is a YouTube link: youtu.be/seSZqi8ajuc
While there is a significant difference between FX and CX cameras in terms ISO performance with still photography…the video performance may surprise folks.
Why do you have to use 1/60th shutter for 30fps video? I use 1/500 for 25fps video on sunny days and I love the motion I get on the videoclip, I can pause the video and see a perfect still photograph, while with a video taken with 1/60 shutter speed I see motion blur in a paused video…. So I think it’s better to shoot video with higher shutter speeds.
The most ‘natural’ and smooth replication of motion occurs when the shutter speed to fps ratio noted (i.e. 1/50 for 25 fps, 1/60 for 30 fps etc.) is used. The blur that you see on a paused frame shot at 1/50th is the exact effect that contributes to the smooth and natural look of the video footage when it is running.
If you are shooting static scenes like landscapes the variance in the shutter speed used will not be as apparent. If you are pleased with the look of your footage when shooting at faster shutter speeds and you like to see ‘stills’ when the video is paused, then there is no reason for you to change it.
I think even my discussion of this is an over simplification as well. I did not want to get into complex discussions about “circles of confusion” and such like which only make it more difficult to understand whats going on for most people. The primary point I wants to make was that depth of field is not directly determined by the sensor – its determined primarily by lens design (specifically the physical size of the aperture in use). But lens design, in turn, is based on the size of the sensor the lens is being designed to provide an image for.
But if you use the same lens once on a large format sensor then again on a small format sensor there should be very little if any difference in OOF blur between the two shots I believe. Except as some have pointed out that because of the crop factor you may choose to change your shooting position. But this has nothing to do with the lens or the sensor. Rather it is a choice the photographer makes.
My point in making this statement is that many people seem to misunderstand what factors affect depth of field and again this is more complex than I wanted to go into in my original post as it also has to do with other factors such as distance from the lens to the subject and effectively the camera format being used (because of the size of the aperture as discussed above).
For example with Ansell Adams, the famous American large format photographer (now long since gone to the great darkroom in the sky) you will see in his photos that he frequently used f stops like f64. Someone once asked how could he do this and not get the image degradation that normally affects lenses because of diffraction effects when you stop down to f stops like f16. But that is only relevant to smaller format cameras like a 35mm film camera. Adams used large format cameras and these had physically larger apertures as befits the large format of the camera, and these had correspondingly smaller depth of field than with a 35mm camera. He needed f stops like f64 because it was the only way to get the extensive DOF he needed. You might well normally expect an f stop of this size to suffer from diffraction issues which causes image degradation if you are a small format photographer. But diffraction like DOF is also a factor of the physical size of the aperture and hence because with a large format camera the physical size of each aperture is larger the diffraction effects are less. Hence he can get away with using f64.
Phew. I think that’s enough for now! Like I said its complex stuff and even the above is a rough and ready partial explanation.
Cheers and good luck all.
Thanks very much for your detailed posting and further insights. It is always a great learning experience when readers share their knowledge and perspectives!
Please make a “definitive” DOF comparison article from Nikon CX to M4/3 to ASC-C/DX to FF/FX even to medium format eg 645d/z or similar. What do you think about it?
My apologies if my article lacked some clarity. My intent was to show that very different types of images can be produced depending on the camera body and lens selected for that image…and this is especially important if, from a creative viewpoint, a photographer wants to have a certain element in the scene to be a particular size in the finished image.
Yes….I did move the camera in order to get the box in the foreground to fill the frame on the right hand side of the image…this was intentional and not meant to mislead in any way. It was simply done to illustrate that if, from a creative standpoint, a photographer wanted to have an element in the foreground filling the frame, that their choice of camera/lens combination can create vastly different versions of that overall image in terms of what is happening in the rest of the frame.
To your point, I took some shots today with a Nikon 1 V2 using the FT-1 and an FX 50mm lens (i.e. 135mm efov) at f4, using the same framing as in this article. Then, I took the exact same shot in terms of framing at 135mm with my 70-200 f/4 @ f/4 on my D800.
The positioning of the boxes in the two images was identical. As would be expected at equivalent fields-of-view of 135mm there is no difference in the size or relative position between any of the boxes in the two images, regardless of the set-up that I used.
But…since I used a 50mm FX lens with the FT-1 adapter on the Nikon 1 V2 to get the equivalent focal length of 135mm there was a difference in the amount of the frame that was in focus, with the 50mm lens producing more depth-of-field than did the 70-200 f/4 at 135mm. So, depending on my intent with the shot I had two very different outcomes based on my choice of camera body and lens.
My article obviously could have done a much better job explaining this point.
As photographers I think it is important for us to consider all of our creative options when we are considering taking an image, and how our choice of camera body/lens can impact the final appearance of our image.
For example, if I want the ‘look’ of a 135mm f/11 telephoto shot, and having that amount of depth of field is critical to me….but if I don’t have enough light to shoot at an f/11 aperture, it’s good for me to know that I can achieve that exact ‘look’ by shooting with the Nikon 1 V2 with an FX 50mm @ f4. I end up in exactly the same place that I wanted to be…just a different route to get there based on the light available to me at that time.
I run into issues like this all the time when I am shooting video since I can’t change shutter speed and I’m limited to ISO-800 when I’m on-site. Being able to mix and match CX and FX lenses on a Nikon 1 to achieve different depth-of-fields to augment my D800 provides a host of creative options.
I actually didn’t have much issue with what you had in your article. My thing was just trying to bring out awareness that all the focal length of a lens does is provide a “crop” of sorts of the image in front of you. It inherently doesn’t provide any additional depth of field if you stand in the same place and change lenses.
Still, it seems like every sensor comparison article brings out people saying that f1.2 is really f2 and f2.8 is really f4, etc. That’s not true at all. But if you try to obtain the same framing it can look true.
In an unrelated thought: I wish the trend of having 1cm (1/2 in) of a person’s face in focus would pass.
It’s not a compressed depth of field you get with the FT1. In order to obtain the same framing as the FX you’ve changed your perspective which changes the visual relationship of the objects in the image. Please help us stop the misinformation out there that focal length has anything to do with compression of the image.
This post has prompted me to go off topic a bit. Sometimes, I can’t just help myself. :)
It has been interesting and entertaining to me that the Japanese term ‘bokeh’ started coming into general use shortly after the appearance of the crop sensor and its lens equivalencies. To achieve coverage equivalent to full frame sensors (or film) necessitated using shorter focal length lenses and their attendant loss in depth of field. Since the laws of physics couldn’t be overcome, user’s ideas of what makes a good photograph might be. While in the past maximum depth of field was sought after (much more often than today) the need to sell product meant a different approach needed to be marketed. A re-education of users has been underway since about the mid 90’s.
With respect, I don’t actually think this proves anything. At least it proves nothing about the characteristics of the sensor. And here is why.
As I understand it you used different lenses for the different cameras. Depth of field is a characteristic which is principally determined by the physical size of a lens’s aperture. Picking an f stop for the sake of the example, f5.6 on a lens designed for a full frame camera will be physically larger than f5.6 on a lens designed for a DX camera and it follows that f5.6 on a DX camera will be larger in its physical size that of a lens designed for a small sensor pocket camera.
F5.6 (or any other f stop) simply means that the same amount of light is delivered to the film / sensor plan at that f stop. it does not mean that all f5.6 apertures are physically the same size. However it is the physical size of the aperture that determines depth of field at any given f stop. A lens which has a larger physical size will give smaller depth of field, other things being equal, as the physical size of each aperture on that lens is larger than it would be on a smaller lens.
For example the physical size of f5.6 stop on an FX camera might be the same as that of f2 on a small format camera . This is why larger cameras have a smaller depth of field, not because the sensor is different but because the native lenses are bigger (as are the apertures in those lenses). In other words, strictly speaking, depth of field has nothing to do with the sensor except indirectly – The size of the sensor determines the design of the lens. In an FX camera everything has to be scaled up in order to provide the coverage needed for proper image capture due to the larger sensor. A larger sensor demands a larger lens and larger lenses must have a physically larger size aperture at every f stop.
Because you have compared apples and oranges I am afraid the test proves nothing except it confirms what I have said above. But it certainly cannot be said that this has anything to do with the sensor per se.
What you need to do is to take a lens designed for a larger format camera (say FX) and use it on its native camera to take some images. Then having done this, take the same lens, and mount it on a smaller sensor camera using an adapter and retake the same images at the same f stops. Then you will see if there is any difference in the depth of field. My bet is that it will be minimal. or possibly the apparent depth of field with the lens mounted on the small sensor camera may look slightly less. This is because an image taken on any small sensor camera must be enlarged more to make it the same size and hence any lack of sharpness / blur will be more apparent.
I’m inclined to agree with peterm here. His main point, and the most important statement is that “depth of field has nothing to do with the sensor except indirectly.” Simply put, sensors (and sensor sizes) do not determine depth of field. Only three things determine depth of field: aperture size, focal length, and distance to subject. It is only because a different sensor size causes changes in those three determinants of depth of field, that you will notice a difference in depth of field between two different sensors. Thomas Stirr may be fully aware of this, but the way he has written the article is misleading–it seems to suggest that the sensor itself affects depth of field, but it does not (except indirectly).
Peterm has identified the different lenses’ apertures as causing the difference, but I’m not sure that even this is entirely correct. In my experience the only important difference between lenses designed for full frame vs. crop sensors is their image circle.
Note that while Stirr has set the same aperture for each comparison, and apparently the same camera-to-subject-distance, the focal length is different. Yes, the field of view is equivalent, but that is precisely what has caused the focal length to be different (for his different sensor sizes), which causes the depth of field to be different.
In other words, the situation that we have is:
different sensor size + similar field of view = different focal length —> different depth of field
And NOT, as Stirr seems to imply:
different sensor size + same aperture = different depth of field
These things are confusing, so it is understandable that mistakes are made. There is a lot of misinformation out there that contributes to confusion. The chapter on lenses in Ansel Adams’ “The Camera” can help.
Hi peterm and Dale Lempa,
My sincere apologies for over simplifying this issue. You are absolutely correct…the sensor in a camera does not directly affect depth-of-field.
Different sensors provide different fields of view with smaller sensors having narrower fields-of-view. So, to achieve the same angle of view as say a 50mm full frame less on a full frame body, a camera with a smaller CX sensor like a Nikon 1, would need to use a wider angle lens…and that wide angle lens would have much more depth-of-field at any given aperture compared to the 50mm full frame one.
If we consider a 50 mm full frame lens on a full frame camera….it has an angle of view of 47 degrees. To achieve this same angle of view on a Nikon 1 camera with its smaller CX sensor using a 1 Nikon lens we would need to use the 18.5mm. This lens has an angle of view of about 46.4 degrees.
So, while the angle of view is virtually the same between a D800/50mm f/1.8G combination and a Nikon 1 V2/18.5 f/1.8 combination, the properties of the lens required to achieve that equivalent field-of-view are very different indeed with the 18.5 wide angle having more depth-of-field at any given aperture compared to the 50mm FX lens.
Again, my apologies for the over simplification in the article.
I do think that your simplification is correct.
For most practical purposes, a photograph fills the frame with his subject, and in order to keep the same perspective effect, he needs to do that from the same distance, then the key factor is the angle of view.
That means that to judge the effect of the sensor size on the depth of field, it is absolutely correct to use two lenses with the same angle of view. And it is correct also to conclude that for the same aperture settings, the smaller the size of the sensor, the greater the depth of field,.
Thanks Tom for your clarification and response to comments.
Don’t get your drift here, Peter.
Thomas has already done, as you suggest, and posted an image taken with the same lens on both the FX and CX cameras. F/5.6 with the 50mm shows considerable less DOF taken on FF than CX (although the apparent focal length should make it the reverse).
What it proves, to those that maybe have not studied in depth the physics of photography, is there is a massive difference in depth of field between FX and CX and accordingly significant consequences.
Thomas’s posting has considerable point to some people who intend to buy gear.
I found myself heavily favouring my Nikon V1 with the 6.7-13 VR and 18.5 for my travels, in fact it was my primary camera for my month my Europe trip late last year (the secondary being the Sigma DP2M). For travel it seems the deeper FOV (relative to the aperture) helps me tell the story better as the final image can show both the foreground and background with sufficient amount of deliciousness.
Initially i miss the bokeh-ness of my FF D600 but slowly i learn that framing was the factor in achieving the desired image. It also came as a surprise to me that the files from the CX sensor are surprisingly robust.
i do sometimes weight the decision to switch to the Sony A7 for increased image quality relative to the weight and mobility. And also the fact that setting changes (exp comp, WB, aperture etc) are seen in real time before i hit the shutter button on the Sony.
Thanks for your posting and sharing your experiences. I also have the two 1 Nikon lenses that you noted in your posting….and I also enjoy shooting with them.
I also relate to the temptation of camera technology….there are so many great cameras from a wide range of manufacturers!