Potential dead horse: how bad is FF's deep DoF disadvantage?

Started 6 months ago | Discussions thread
Steen Bay
Veteran MemberPosts: 6,188
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Re: no disadvantage
In reply to joejack951, 6 months ago

joejack951 wrote:

Steen Bay wrote:

joejack951 wrote:

tko wrote:

And I own a FF lens that stops down to F/50 or something silly.

What lens? My 105VR will display f/57 when stopped down to f/22 and at minimum focusing distance, but that's just Nikon's way of displaying the light loss at close focus distances (effective aperture as explained in the lens manual). DoF is still f/22.

If you shoot af f/22 at 1:1 magnification, then I think that you're effectively shooting at app. f/44 in terms of both exposure, DoF and diffraction. Kind of like using a 2x TC.

I misspoke when I said f/22. The 105VR stops down to f/32 and will display f/57 (IIRC) at minimum focusing distance.

Unless I've always read/understood incorrectly, effective aperture only affects exposure. DoF and diffraction are not affected because the aperture blades aren't actually moving. TC's have glass in them that changes the image being projected by the lens. That's a lot different than moving the lens elements further from the sensor (like an extension tube).

I swear that my lens manual went into detail about this but the Nikon lens manual online mentions nothing about effective aperture. Weird. I need to check that when I get home.

Any care to chime in on the true effects of shooting up close?

Found a bit about it here : http://www.cambridgeincolour.com/tutorials/macro-lenses.htm

"However, at high magnification the effective f-stop is actually what determines the diffraction limit — not necessarily the one set by your camera."

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