Prospective m4/3 Owner: Action Issues; Birding

Started Nov 23, 2012 | Discussions thread
Dennis Linden
Junior MemberPosts: 25Gear list
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Re: Prospective m4/3 Owner: Action Issues; Birding
In reply to jim stirling, Nov 25, 2012

jim stirling wrote:

Dennis Linden wrote:

Jim F wrote:

Also consider this, the 75mm f1.8 lens is the equivalent of 150mm f1.8. $900 vs 5000 ?? or some such. the Olympus 75-300 is a 600 mm equivalent lens and shooting in bright light would be a great lens.

No the 75mm is absolutely not equivalent to a 150mm F1.8 , in regard to total light reaching the sensor , as is well known an f1.8 mFT lens will give the exact same effect as a FF 150mm at F 3.6 ( how's that $900 dollars working out now) with regard to total light, Dof and AOV.. The Olympus 75-300 is F6.7 at the long end and honestly about every single image posted from it at the long end is soft. Look at the lack of detail in the birds feathers in any of the moving images posted. I really feel that many of the shots we see in the forum are more down to the huge DOF ( helped by both the smaller mFT sensor and very slow lenses ). I have not seen a critically sharp moving bird shot

I don't mean to be critical BIF are one of the most difficult areas photography has to offer. I have seen very few convincing shots in the forum and if this is a critical need for a user then there are better choices band faster lenses in dslr land.

Jim

Actually Jim, they are working out just fine. Your premise is based on equivalent DOF, not light transmission. IE, on a 4/3 sensor the 75mm at f 1.8 would give a similar AOV and DOF as a 150 at f3.6. That does not mean the f 1.8 lens is transmitting less light. And for my purposes, it's the light I am after.

Clearly, greater DOF actually helps with the focusing problem. That is the premise: the smaller the sensor, the greater the DOF.  I am no lens engineer or physicist, but I can from personal experience say that the 75 f1.8 allows me to get much faster exposures than you seem to be implying I should.

You have a point that the 75-300 could use a much faster aperture, couldn't we all.

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