Where have all the Focal-reducers gone? (with apologies)

Started Feb 3, 2014 | Discussions thread
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Re: Where have all the Focal-reducers gone? (with apologies)
In reply to 5nex7, Feb 5, 2014

5nex7 wrote:

My point is: can a longer slower lens focal reduced can do much.. or less the some thing as an inherently faster lens of shorter focal length ?

Let us use a 35mm f/2 lens as an example. Put it on an APS-c camera and you get, 50mm FOV equiv, f/2.8 DOF equiv and f/2 shutter speed equiv.

Add SB. Now, you can get an effective 25mm f/1.4 lens (about 37mm f/2 equiv). Sure, you can go buy a 24/1.4 lens... if available and your budget permits.

At the other end, I have Minolta 70-210/4, which works like a 105-320mm f/4 lens on APS-C. But, I can also use it as a 50-150/2.8 lens (75-225 f/2.8 equiv).

91mmF1.2 full frame equivalent, 60mmF1.2 real length, so you should compare it to 55F1.2 on APS-C.

If you have 85/1.8 and an APS-c camera, you get 130mm f/2.8 equiv lens but with f/1.8 shutter speed.

If you use SB, combined with 85/1.8 you already have, you get 60/1.2, which gives you 90mm (FOV) f/1.8 (DOF) with f/1.2 shutter. Of course, you can skip SB and shop for a 55/1.2. But, you may have to do so with every lens, instead of carrying an adapter.

The buy a lens approach will be useful if you must have AF but at a cost and bulk.

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