OM-G

Lives in Norway Norway
Joined on Jul 2, 2020

Comments

Total: 5, showing: 1 – 5
In reply to:

OM-G: Equivalence has a flaw.

It only works 100% if you leave out AF/metering.

A 1/2.3" sensor will focus just fine at f5.6 (like a 2016 TG 870 with max f5.7 at the tele end), but will FF do the same at the equivalent f32?
Or how about the equivalent f64 on a 0.5x medium format, will it AF?
Things would be more equivalent if the FF did focus at f5.6 and then stopped down to f32 when the shutter fired.

The FF equivalent to 300mm f4 mFT lens will in this regard be a 600mm F4 lens stopped down to F8, not a 600mm F8 lens. It would then focus/meter at F4 and gather light at F8.

spider-mario, the light on the sensor would be to dim for any AF to work. F5.6 is still F5.6 on a small sensor, so things like AF and metering will work fine. Neither would work well with a max aperture og F32

Link | Posted on Jul 4, 2020 at 11:42 UTC

Maby they are staying in the lens business, and just selling the body business..
When they have all these lenses, everyone will want to make a mFT camera :)

Link | Posted on Jul 3, 2020 at 19:51 UTC as 13th comment
In reply to:

Jones Indiana: Interesting, but an f4 lens stays an f4 lens.
This is the advantage of having a smaller sensor size.

However with the high resolution sensors found these days in Full Frame cameras like the Z7 and A7Riv, you'd basically also own both a 20.1MP+ APS-C camera and 24MP+ MFT camera.

That makes you already own a 400mm f2.8 for MFT and a 300mm f2.8 APS-C lens if you own the 70-200mm f2.8.

If you are not fortunate enough to be able to afford a 70-200mm f2.8 there is always the choice for going with an 70-200mm f4.0. which is a lot more affordable (and saves you a ton of weight), but still giving you the 400mm or 300mm equivalent focal length at f4, just by cropping the image.

So why bother for slow lenses while you can have fast lenses with the same focal length, just by cropping the image.

There is no automatic 2-stop advantage to low light AF for FF vs mFT.
AF has more to do with light per area, and here F4=F4.

An EM1 mkIII with a 300mm F4 will have around a 2 stop advantage in low light AF compared to a Sony A7S II with a 600mm F8 lens.

Focus sensitivity for the Sony is EV-4 (ISO 100 with F2.0 lens)
Focus sensitivity for the Olympus is EV-4.5 (ISO 100 with F2.0 lens)

Same thing applies to exposure metering.

Link | Posted on Jul 3, 2020 at 14:40 UTC
In reply to:

OM-G: Equivalence has a flaw.

It only works 100% if you leave out AF/metering.

A 1/2.3" sensor will focus just fine at f5.6 (like a 2016 TG 870 with max f5.7 at the tele end), but will FF do the same at the equivalent f32?
Or how about the equivalent f64 on a 0.5x medium format, will it AF?
Things would be more equivalent if the FF did focus at f5.6 and then stopped down to f32 when the shutter fired.

The FF equivalent to 300mm f4 mFT lens will in this regard be a 600mm F4 lens stopped down to F8, not a 600mm F8 lens. It would then focus/meter at F4 and gather light at F8.

There is no automatic 2-stop advantage to low light AF for FF vs mFT.
AF has more to do with light per area, and here F4=F4.

An EM1 mkIII with a 300mm F4 will have around a 2 stop advantage in low light AF compared to a Sony A7S II with a 600mm F8 lens.

Focus sensitivity for the Sony is EV-4 (ISO 100 equivalent with F2.0 lens)
Focus sensitivity for the Olympus is EV-4.5 (ISO 100 equivalent with F2.0 lens)

Same thing applies to exposure metering.

The point is that you cant just take a FF system with a 2-stop slower lens and think its equivalent in every aspect, each system has its strenghts.

Link | Posted on Jul 3, 2020 at 08:19 UTC

Equivalence has a flaw.

It only works 100% if you leave out AF/metering.

A 1/2.3" sensor will focus just fine at f5.6 (like a 2016 TG 870 with max f5.7 at the tele end), but will FF do the same at the equivalent f32?
Or how about the equivalent f64 on a 0.5x medium format, will it AF?
Things would be more equivalent if the FF did focus at f5.6 and then stopped down to f32 when the shutter fired.

The FF equivalent to 300mm f4 mFT lens will in this regard be a 600mm F4 lens stopped down to F8, not a 600mm F8 lens. It would then focus/meter at F4 and gather light at F8.

Link | Posted on Jul 2, 2020 at 14:44 UTC as 58th comment | 4 replies
Total: 5, showing: 1 – 5