Nikon D700 AV limit with 60mm macro lens?

antonroland

antonroland

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Hello everyone

I really do not understand why this is happening but I have tried everything I could think of. I simply can not get the lens / body combination to f/2.8.

It occasionally shows f/2.8 but the moment you touch the shutter button it jumps to anything between f/3 and f/4.8:shrug::thinking::bang:

We have 5 of them and they all do the same thing!

I have switched off all the dummy features I could find and reset the shooting menu and custom functions.

Anyone have any idea why this is?

Cheers!:thumbs:
 
Do you not get 2.8 even when focusing at infinity? The aperture is supposed to stop down as you focus closer on these lenses.
 
hyeongsoong said:
that is normal on a micro lens when focus something close.
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jpw said:
Do you not get 2.8 even when focusing at infinity? The aperture is supposed to stop down as you focus closer on these lenses.
Click to expand...

I do not understand why this is or should be, folks...neither Canon nor Pentax does this?

I will investigate the infinity thing and report back on that, thanks!

Still, unless some default setting somewhere is messing me around I should surely be able to use a f/2.8 lens at f/2.8 regardless of working distance?:shrug::shrug::shrug:

Thanks for the responses!:thumbs:
 
jpw said:
Do you not get 2.8 even when focusing at infinity? The aperture is supposed to stop down as you focus closer on these lenses.
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I do get f/2.8 at infinity and even moderate non-macro distances.

The moment I get into macro distances it stops down...:shake: WHY?

I mean, why must the lens stop down thereby robbing me of the f/2.8 capability which, admittedly, being macro is not very shallow anyway?:bang:

Is there a workaround for this? It does this even in full Manual!:bang:
 
All lens makes do this but Nikon report the actual aperture whereas cannon do not. No real mystery to it and is in the nature of macro lenses. Not that f2.8 is of any use to anyone at the minimum focal distance of most macro lenses!
 
Perfectly normal, just dont worry about it. Its physics...
 
antonroland said:
I do get f/2.8 at infinity and even moderate non-macro distances.

The moment I get into macro distances it stops down...:shake: WHY?

I mean, why must the lens stop down thereby robbing me of the f/2.8 capability which, admittedly, being macro is not very shallow anyway?:bang:

Is there a workaround for this? It does this even in full Manual!:bang:
Click to expand...

Nikon lenses are reporting something that other brand lenses neglect to report. It happens to all lenses, which you could show if you have a friend with another brand macro.
 
menthel said:
All lens makes do this but Nikon report the actual aperture whereas cannon do not. No real mystery to it and is in the nature of macro lenses. Not that f2.8 is of any use to anyone at the minimum focal distance of most macro lenses!
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TCR4x4 said:
Perfectly normal, just dont worry about it. Its physics...
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Now you guys have me curious and suspicious at the same time...:p

So Canon and others are lying to us, eh? will check that out!

Any more info to point me in the direction of the physics answer?

Admittedly, yes, wide open at very close macro distances 1:1 to 1:2 is something I do from time to time but not every day...but what you guys are now telling me what I thought was f/2.8 could have been f/3.5 or even worse...made me think...:suspect:

Cheers all!
 
when focusing at very close distances, the actual size of the lens opening doesn't change, but less light is getting through. and when nikon cameras show a drop in aperture in their display they are referring to light not the actual size of the aperture.
 
hyeongsoong said:
when focusing at very close distances, the actual size of the lens opening doesn't change, but less light is getting through. and when nikon cameras show a drop in aperture in their display they are referring to light not the actual size of the aperture.
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But this makes no sense at all because the quantity of light can be corrected by adjusting the duration of the exposure...:thinking:

This then is what really puzzles me, if I have a f/2.8 lens at f/2.8 and I focus it at 1:1, I cannot obtain a true exposure at f/2.8 because the camera is fooled into thinking f/2.8 is actually f/4...

Why bother building a macro lens at f/2.8 then? Makes no sense to me...:bonk:
 
Well, I learned something today...still don't quite understand it but, hey...

Also saw this:

http://www.kenrockwell.com/canon/lenses/100mm-f28-is.htm#loss

Now, it being on this guy's site I take it with a bucket of salt but for those who might be interested, here it is...:p

Maybe now I can take a break from planet Geek and get on with my life:naughty:

As soon as I saw how the physics....:help:
 
This is a job for HoppyUK lol.

It's normal behaviour and I did read once why this happens but forgot- Hoppy!?

That's why the 105mm f2.8 can't accept a tele on bodies which don't AF at f8, the maximum aperture is too small.

Bit annoying that we are lead to it's not advertised about this behaviour.
 
Phil Young said:
This is a job for HoppyUK lol.

It's normal behaviour and I did read once why this happens but forgot- Hoppy!?

That's why the 105mm f2.8 can't accept a tele on bodies which don't AF at f8, the maximum aperture is too small.

Bit annoying that we are lead to it's not advertised about this behaviour.
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Let's hope he sees this!

Cheers:thumbs:
 
antonroland said:
So Canon and others are lying to us, eh? will check that out!
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Not lying, it's just that Canon et al. report the set aperture while Nikon report the actual aperture.
 
This from another forum a few years ago explains the reason in simple enough terms

F-numbers engraved on the lens indicate the aperture at infinity. As any lens focuses, the optical center (nodal point) moves away from the film/sensor plane, but the aperture diameter remains constant.

However, by the inverse square law, the amount of light reaching the film/sensor plane decreases. When shooting at life size, the light loss is two stops. At ½ life size, a one-stop reduction occurs.

It doesn’t have to be a macro lens—this happens to any lens, especially macro lenses, or a lens attached to extension tubes or bellows. You just don’t notice the light loss with non-macro lenses because the lens' focal length is much greater than the film plane / sensor plane to optical center distance when the lens is focused to its closest point.
 
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