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.