90mm Aperture issue...

[photographique]

I just bought a Tamron 90mm Macro lens, I thought it had fixed aperture.

However, when I tested it on my D200, the aperture was not fixed. It was like varying with focusing movement, and could hardly stay at F2.8...even in manual mode.

Anyone can help?

Thanks!

[TMC]

Its a macro lens, the aperture will change when you focus in very close. It is the way it is designed. Read more about it.

[photographique]

Originally Posted by TMC Its a macro lens, the aperture will change when you focus in very close. It is the way it is designed. Read more about it.

Ok, is that the reason why sometime a distant object can be focused at F2.8?

I heard from some people who claimed that they can hav fix aperture with that lens?

[TMC]

when you used it as a regular lens, it will function as a fixed aperture prime. But when you go down to macro distance, the aperture value will change to reflect that.

read up on this.
http://www.nikonians.org/dcforum/DCForumID6/1927.html

[photographique]

Originally Posted by TMC when you used it as a regular lens, it will function as a fixed aperture prime. But when you go down to macro distance, the aperture value will change to reflect that. read up on this. http://www.nikonians.org/dcforum/DCForumID6/1927.html

Thanks for your help.

How much is the macro distance?

I do get 2.8 when focusing at distant objects, but it fluctuates, doesn't seem like a Prime lens characteristic...

[majere2sg]

Originally Posted by photographique Thanks for your help. How much is the macro distance? I do get 2.8 when focusing at distant objects, but it fluctuates, doesn't seem like a Prime lens characteristic...

Should be around 24 to 27cm if I am not wrong. I think the instruction manual that comes wit h the lens mentioned that.
If I am not wrong, for canon mount, it stays at f/2.8 as it does not report the actual aperture at macro distance. Used to have one for canon mount, great lens.

[seankyh]

In any case when shooting macro, I don't use wide open apetures. Usually go with f8-f13 depending on availble light. With the apeture wide open, its difficult to get anything in focus

[lsisaxon]

Originally Posted by photographique I just bought a Tamron 90mm Macro lens, I thought it had fixed aperture. However, when I tested it on my D200, the aperture was not fixed. It was like varying with focusing movement, and could hardly stay at F2.8...even in manual mode. Anyone can help? Thanks!

The aperture is still fixed. The reported aperture is used to compensate for the light fall off because of the extension at macro focusing distance.

[ipin]

There's nothing wrong with your lens.
Sharp lens at it's price range!

[zac08]

It's the same with the other macro lenses... try the others out and you'd see that they all change aperture when you're focusing close...

[photographique]

Ok, thanks for all your help and info.

Yes, it does a good job when focusing on distant objects, and the object has to be say around at least 3-4 meters away to be @ F2.8, is that normal?

[ipin]

Originally Posted by photographique Ok, thanks for all your help and info. Yes, it does a good job when focusing on distant objects, and the object has to be say around at least 3-4 meters away to be @ F2.8, is that normal?

do read the manual. IMO it's less than 3-4 meters away.

[photographique]

Originally Posted by ipin do read the manual. IMO it's less than 3-4 meters away.

I think it only says that the aperture changes with focusing movement...

[ipin]

Originally Posted by photographique I think it only says that the aperture changes with focusing movement...

My manual says 0.29m leh. Are we talking about the same thing?
Besides :

Originally Posted by lsisaxon The aperture is still fixed. The reported aperture is used to compensate for the light fall off because of the extension at macro focusing distance.

Does the above answer your question?

[photographique]

Originally Posted by ipin My manual says 0.29m leh. Are we talking about the same thing?

Hmm...0.29m is the minimum focusing distance. I was talking about beyond what distance the aperture is f/2.8, my only focuses @ f/2.8 on distant objects...at least a few meters away.

[ipin]

Originally Posted by photographique Hmm...0.29m is the minimum focusing distance. I was talking about beyond what distance the aperture is f/2.8, my only focuses @ f/2.8 on distant objects...at least a few meters away.

Mine can be @ f/2.8 on subjects closer than 1m leh.

[catchlights]

nothing wrong with your lens, the effective aperture changed due to light loss of close distant focusing, the extending of lens barrel.

you can have the info you want in your manual of the tamron lens

[photographique]

Originally Posted by ipin Mine can be @ f/2.8 on subjects closer than 1m leh.

That's the confusing part...how come mine is not like that? Most of the time is f/3, btw could it my camera problem?

[ipin]

Originally Posted by photographique That's the confusing part...how come mine is not like that? Most of the time is f/3, btw could it my camera problem?

I'm also using the D200. You using the MF or AF version of the Tamron 90mm?

[photographique]

Originally Posted by ipin I'm also using the D200. You using the MF or AF version of the Tamron 90mm?

SP AF Di 90mm Macro...sigh, what's blardy problem or just my own confusion, but after all it's just a macro lens...not a prime.