Micro 4/3rds vs. Full Frame: Macro and Still Life Photography Forum: Digital Photography Review (2024)

photojoe55 wrote:

Am I correct that in Macro work, the main advantage of Full Frame is due to the sensor size, (1:1 = 1:1 and it is simply quite a bit larger) and a main advantage of a smaller sensor like micro 4/3rds is an increased Depth of Field? If that is correct, would an even smaller sensor like in the FZ300 produce an even greater Depth of Field?

I have a particular interest in this, having used the FZ300 a lot for photographing insects etc and now using full frame instead. I'm afraid this got rather long and detailed. Please feel free to ignore.

An MFT camera will give greater depth of field than a full frame camera for a given f-number, let's say f/8. A 1/2.3" sensor camera like the FZ300 will give even greater depth of field at f/8.

However, for a given scene you can get greater depth of field with a full frame camera or an MFT camera than with an FZ300

I know, this doesn't sound right. However ....

The FZ300 is a fixed lens camera. Like many small sensor cameras it has a macro mode. This lets you focus down to a scene width of around 40mm, with a working distance between the lens and the subject of 10mm. This short working distance and relative large minimum scene size is not suitable for a lot of small scenes, especially when it comes to insects and other invertebrates. That means that the only practical approach with a camera like the FZ300 for shots like the two below is to use close-up lenses.

This one used a Raynox 150 close-up lens and would have had a working distance of around 200mm.

This red mite is rather smaller, with the body around 1mm long, and it would have used a more powerful close-up lens setup, possibly a Raynox 250, in which case the working distance would have been around 120mm, or possibly something stronger, in which case the working distance would have been shorter.

You will see that both of these used f/8, which is the minimum aperture for the FZ300, which gives the maximum depth of field which can be achieved with the camera and others like it.

With a full frame camera using a macro lens, the minimum aperture is likely to be f/22. (It is f/16 for some macro lenses and f/32 for some others, but for now let's assume that it is f/22. And let's also assume that it isn't a Nikon setup, which works a bit differently.)

With the lens set to f/22, we call f/22 the "nominal f-number". However, the actual f-number you are using, known as the "effective f-number", is different. It can be calculated approximately using the following formula. (There is a more complicated and more accurate formula, but it includes a term which generally isn't known for a particular lens, so this is the simplification that is generally used.)

Effective f-number = Nominal f-number * ( 1 + magnification )

So for example if you set the lens to f/22 and shoot at 0.5X magnification (1:2) the effective f-number is approximately

f / 22 * ( 1 + 0.5 ) = around f/32

If you set the lens to f/22 and shoot at 1:1 the effective f-number is approximately

f / ( 22 * ( 1 + 1 ) = around f/45

If you set the lens to f/22 and shoot at 2X (2:1) the effective f-number is approximately

f / ( 22 * ( 1 + 2 ) = around f/64

So as the magnification goes up, the effective f-number gets larger and the effective aperture gets smaller. With a smaller effective aperture, depth of field increases (and so does the amount of detail lost from diffraction softening).

However, when using close-up lenses the effective f-number does not change as the magnification changes. That means that if you shoot with minimum aperture of f/8 with an FZ300 for example then you are using f/8 whatever the magnification. Because of the difference in sensor sizes, f/8 on a 1/2.3" camera like the FZ300 gives around the same depth of field as f/45 on full frame. And this gives the maximum depth of field which is possible with the FZ300.

However, with a full frame camera you can push the effective aperture beyond f/45 if you increase the magnification enough. So with your macro lens at f/22, at any magnification greater than 1:1 you will get greater depth of field than you can with the FZ300. If you are using a macro lens that only goes to f/16, like the Canon MPE-65, then you have to get to 2:1 before you can match the depth of field from the FZ300 at f/8. However, beyond that (and the MPE-65 goes out to 5X magnification) you can get greater depth of field than with the FZ300.

This is why, after using close-up lenses for over a decade, most often on cameras like the FZ300 and its FZ200 predecessor and earlier the similar Canon SX10is, I switched to using a full frame camera, so I could get greater depth of field and achieve results I couldn't with my small sensor bridge cameras.

With full frame I now work routinely with f/11 set on the lens and a pair of 2X teleconverters, which combine to give a nominal f-number of f/45 (f/(11*2*2). When I set 1.5X magnification on the lens, this gives 6X overall magnification with the two teleconverters (1.5X * 2 * 2) and that is around what I use for subjects like this, with an effective f-number of around f/112 (45*(1+1.5)).

The most extreme example I have is this one, which used f/22 on the lens to give a nominal f/number of f/90 (22*2*2) and 2X magnification set on the lens for total magnification of 8X (2 * 2 * 2) and an effective f-number of around f/270 (90 * ( 1+2)).

Bear in mind though, that there is a cost that comes with these greater depths of field, and that is greater loss of fine detail from diffraction softening. I use post processing to try to make something usable from the very soft images I get when using very small apertures.

I could get even greater depth of field with MFT by using the same lens and teleconverter setup on MFT, However with the full frame I have already reached the limit of what I can handle in post processing by way of diffraction-softening from small apertures, and so although I could get greater depth of field using the same lens and teleconverter setup on MFT the images would be too soft and lacking in detail for me to make use of.

Thank you in advance, …Joe