Let's reverse the narrative and see what happens logically.

Started 5 months ago | Discussions thread
guy_incognito1 Junior Member • Posts: 42
Re: Let's reverse the narrative and see what happens logically.
1

George1958 wrote:

I thought DoF and aperture were optical effects ? There are differences in the characteristic of different formats but F1.8 is F1.8. As far as I know there are no FF primes that weigh as little as these M4/3. I accept that the FF sensor combined with good lenses will deliver an optimal image quality. In most circumstances other than low light so will M4/3

17mm F1.8 120g

25 min F1.8 137g

45mm f1.8 116g

The problem is MFT's most hated word, equivalence. (cause really there is no such thing as equivalence). Because DOF gets thinner as focal length increases more than DOF gets thicker as sensor size increases.

So if your goal is thin depth of field for nice currently in-style bokeh:

Say on MFT, you like your 17mm f/1.8 and take a photo, and like your product.

Since the FF sensor is larger, if you want the same framing and use your full sensor instead of cropping, you use a 35mm lens instead of 17mm.

For a 35mm lens on FF to have similar DOF to a 17mm f/1.8 on MFT, you would use f/3.6 (and you can use the light samyang 35mm f/2.8 at 108g and stop it down) and you end up with a photo with same framing and DOF.

MFT fans though always like comparing FF to nice value and sized MFT lenses, which is kind of a biased comparison.  Instead, if you look at it the other way, comparing to the good value and sized FF options.

Like say you liked the output of your sony FF 50mm f/1.8 (186gm, $250) wide open, and you wanted to compare it to MFT.  You would need a 25mm f/0.9 to get equivalent DOF, which doesn't exist, so no comparison really is possible.  If you compare it to the closest thing,  like olympus 25mm f/1.2 (410gm $1150) then MFT doesn't have an advantage in size and price anymore.

But it's not completely 100% equivalent, because of differences of perspective distortion by the different focal lengths and by the differences in exposure (not to mention differences in actual real life specific model lens performance and performance of FF over MFT sensors at same exposure).

So to get a similar framing, DOF, AND exposure, FF would need to have a shutter speed 4x slower.  But, as many people point out, depending on the situation, you could just open up your FF camera, and have a thinner DOF than possible on MFT and have the same SS, which covers a lot of the real-world use scenarios.

Post (hide subjects) Posted by
MOD Smaug01
MOD Smaug01
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
(unknown member)
lft
lft
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow