Hoods for legacy lenses used with NEX?

Started Feb 2, 2013 | Discussions thread
KM Legacy Senior Member • Posts: 1,955
Re: Hoods for legacy lenses used with NEX?

Photozopia wrote:

KM Legacy wrote:

But I guess all the optical engineers who design that stuff are ignorant of "basic science."

And engineers used that basic science - designing hoods to stop (average) stray light source entering a specific lens. Stop the source - stop the flare - simple.

Your argument is essentially (but contradictory) equivalence-derived BS.*

The equivalence crowd would have all believe something magical or odd happens when putting a FF lens on a smaller sensor ... in this scenario nothing happens, other than a crop of it's image circle by smaller sensor dimensions.

There is no 'excess light' ... i.e. 'unused' photons spilling from BIGGER lenses into the sensor/mirror chamber - not does the FF lens now have any greater/wider angle of view, thus capturing more light. It's front element (the primary source of flare) remains unaltered - it's internal baffling or construction methods (the stuff you so 'patronisingly' pointed out in your response) remains totally unaltered.

No new factor of flare is created or introduced. No new light leak or light source enters the lens' front or rear exit pupil. The optical flare path/suppression capacity is unaltered. Nothing changes or alters in the lens bar a crop by sensor ... so the hood that sufficed on FF suffices now. QED.

A 'narrower' hood ... perhaps a 'capacity' or 'vacuum' (strictly speaking) for one exists - because of the central crop factor .... BUT IS NOT NEEDED.

(* If pseudo-equivalence BS is followed, a 'wider' hood is actually indicated. EQ Theory would argue that FF v APS lens use gains/loses a stop to crop-factor .... so the equivalent f4 of an f2.8 lens on APS means less light ... so less need for hoods ... if we believed your version of 'physics' ....)

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