Just how shallow DoF can M43 achieve - car photography?

woof woof said:

But it's not focal length as such which does this is it? It's the aperture and the camera to subject distance and the distance between the foreground and background elements in the picture. We should be able to see this if we shoot MFT and FF and set the focal length and aperture to take account of the crop factor. So, MFT at 25mm and f1.4 will be near as damn it the same as FF at 50mm and f2.8 and the same will be true of any combination of focal length and aperture for which you can incorporate and match the x2 crop factor (for MFT or x1.5/1.6 for APS-C.)

The difference in how the background appears in your examples is due to the differing camera to subject distances to maintain the subject at the same size. If you shot from the same distance you'd get different framings for each shot but if you then cropped the shots so that they looked the same... they'd look the same... including the larger background effect of the longer lens. The difference between the shorter and longer focal length shots is simply due to the size of the foreground relative to the background and this is due to camera to subject distance.

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I'm just making the point that 'subject isolation' is about more than depth of field. There are other contributing factors.

Using the method suggested in your second para would result in different depth of field - the two images would not look the same.

HoppyUK said:

I'm just making the point that 'subject isolation' is about more than depth of field. There are other contributing factors.

Using the method suggested in your second para would result in different depth of field - the two images would not look the same.

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Yes, the DoF will be different but the size of the foreground and background elements in the image will be the same and that's what I was talking about in para 2, not DoF, sorry for any confusion.

It's not focal length as such which creates the larger background in your example shots whilst the foreground elements remain the same size it's camera to subject distance... I think... It's a confusing subject and this was my point. OK, we're talking mostly about getting shallow DoF from MFT but I thought it worthwhile to mention camera to subject distance relative to your shots for clarity. Yes, using a longer focal length and increasing your camera to subject distance will make the background look larger relative to the subject and this can indeed create a shallow(er) DoF look.

That's one good option when trying to get a shallow DoF look from a smaller format. So, if we have a FF camera and a 85mm f1.4 lens we're going to struggle to get the same image from MFT and a 42.5mm f1.2 (or whatever it is...) but we can maybe get the look we want from using a longer lens on MFT, using a wide aperture and backing up.

Or, as I said, we can shoot a series of images and just pick the one that's nearest to what we like as the differences between apertures wider than (say) f2.8 are arguably, minimal in some shots and if seeing a MFT f1.4 shot in isolation we may be very happy with it and we do still have the options of using longer lenses (85mm f1.8 and f2 are easy to get hold of) or altering our framing and yes, getting a different shot, but it may be one we're happy with

PS. My shots of my MX5 are all different and none are the same (or as good) as the original examples but in a better location and with more time I think that even I could get a bit closer to the original shots quality and even if the MFT shot is always different it may be good enough Personally I don't see the DoF difference between FF and either MFT or APS-C as being all that significant and the smaller formats give me enough creative scope but it's a personal decision that we have to make for ourselves.

woof woof said:

Yes, the DoF will be different but the size of the foreground and background elements in the image will be the same and that's what I was talking about in para 2, not DoF, sorry for any confusion.

It's not focal length as such which creates the larger background in your example shots whilst the foreground elements remain the same size it's camera to subject distance... I think... It's a confusing subject and this was my point. OK, we're talking mostly about getting shallow DoF from MFT but I thought it worthwhile to mention camera to subject distance relative to your shots for clarity. Yes, using a longer focal length and increasing your camera to subject distance will make the background look larger relative to the subject and this can indeed create a shallow(er) DoF look.

That's one good option when trying to get a shallow DoF look from a smaller format. So, if we have a FF camera and a 85mm f1.4 lens we're going to struggle to get the same image from MFT and a 42.5mm f1.2 (or whatever it is...) but we can maybe get the look we want from using a longer lens on MFT, using a wide aperture and backing up.

Or, as I said, we can shoot a series of images and just pick the one that's nearest to what we like as the differences between apertures wider than (say) f2.8 are arguably, minimal in some shots and if seeing a MFT f1.4 shot in isolation we may be very happy with it and we do still have the options of using longer lenses (85mm f1.8 and f2 are easy to get hold of) or altering our framing and yes, getting a different shot, but it may be one we're happy with

PS. My shots of my MX5 are all different and none are the same (or as good) as the original examples but in a better location and with more time I think that even I could get a bit closer to the original shots quality and even if the MFT shot is always different it may be good enough Personally I don't see the DoF difference between FF and either MFT or APS-C as being all that significant and the smaller formats give me enough creative scope but it's a personal decision that we have to make for ourselves.

Click to expand...

Yes, you will get the same amount of background in the image, but they won't look the same because the cropped version will have more depth of field.

For max subject isolation:
- Move subject away from the background.
- Use a longer lens.
- Use lowest f/number.
- Fill the frame with the main subject.
- Don't crop, as that effectively reduces the sensor format, and increases depth of field.