Time to rethink the KIT LENS idea?

Started 4 months ago | Discussions thread
Rod McD
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Re: Time to rethink the KIT LENS idea?
In reply to Leandros S, 4 months ago

Leandros S wrote:

Rod McD wrote:Why focus on and worry about whether a Zoom is constant aperture or not? It used to matter back in the pre-TTL flash days, because you had to recalculate your aperture for flash photography if you zoomed a variable aperture zoom. So, the "pro" lenses all became constant aperture lenses. In these days of flash automation, I can't really see why it matters.

It's just annoying that inconstant aperture causes a communication problem between you and the camera. You set your camera for a particular scene, setting, let's say, f/4. Let's say that that's your available widest aperture at that FL. You then zoom in and get stopped down to f/5.6. It annoys you that you now have excess DOF.

Zooming in decreases DOF.  The change in the DOF due to zooming in (ie increasing FL, decreasing DOF) is greater than the change caused by the changing aperture.  Check out the engraved DOF lines on a zoom that dates from the days when they used to do that - the DOF never increases as you zoom in and that's true for every aperture.  And in zoom lenses with very long zoom ranges, like the 18-135, the change in the DOF due to change in FL from wide to tele is massive while the aperture changes a mere 1.5 stops.

You then zoom all the way back out, but you're still at f/5.6 because your camera doesn't know that you want to shoot the wide angle shot at ISO 100 rather than ISO 400, and want the addtional light of f/3.5 rather than having any requirement for DOF at that point. Even if your camera thinks to put you back at f/4 or tracks the edge down to f/3.5, this may still not be what you're intuitively expecting the camera to do, and it's just one more thing to occupy your mind while you're trying to fix a gazillion other things.

Maybe it's too late in the night here, but although I'd agree that one might have to do some mental gymnastics in photography every so often, I've rarely been troubled by variable aperture unless it related to manual flash calculations.  (It also relates to automated flash at the upper limit of the flash's power).

Yes, arguably it is a flaw in the way we think about aperture, and maybe we should just take a chill pill, but it looks like it's here to stay.

Certainly seems to be! It comes down to what you like anyway.

Cheers, Rod

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