Is Tamron 90/2.8 rather a 90/3.0?

I am very happy with my macro lens Tamron 90/2.8. I have discovered though that the largest aperture that my D100 reports is f/3.0 (the maximum aperture varies with the focusing distance, but f/3.0 really is the largest aperture).

Is there any other Tamron 90 user in this forum that get f/2.8?

Best regards,
Sven

Sven,

This is also happen on my D100 and should be normal, it don't happen on F100 I think most porperly the chip inside has different communication between D100. Remind you that this is not real F2.8 on whole focus distance and only get max aperture around inf. focus distance.
Enjoy it, it is a very good macro len.

Roy

Sven Hedlund said:

I am very happy with my macro lens Tamron 90/2.8. I have discovered
though that the largest aperture that my D100 reports is f/3.0 (the
maximum aperture varies with the focusing distance, but f/3.0
really is the largest aperture).

Is there any other Tamron 90 user in this forum that get f/2.8?

Best regards,
Sven

Click to expand...

Sven Hedlund said:

I am very happy with my macro lens Tamron 90/2.8. I have discovered
though that the largest aperture that my D100 reports is f/3.0 (the
maximum aperture varies with the focusing distance, but f/3.0
really is the largest aperture).

Click to expand...

The largest aperture of the Tamron 90mm SP is F2.8. When you focus the lens to a closer subject, the lens barrel extends becoming longer. This causes light loss while it traverses inside the lens barrel. As a result, F2.8 will be reduced to some smaller aperture. In some worst situations, it could become F5.3 and even F5.6 when the lens is focused at its shortest focusing distance. This is independent of the camera being used.

CK

...the Exifs datas show that the focal length is NOT 90 mm. but 89 mm. (on my Fuji S2 Pro) !!!
...Can you check an let me know what focal you see in your Exifs ?

TIA,

Cheers,
Jean-Pierre
Pbase and DPReview supporter
Go have a look at : http://www.pbase.com/scherrer

Now I know that it is not my lens that is faulty. Unfortunately, I will not have access to camera or images in a couple of days, so I cannot check the FL reported in the EXIF yet.

Regards,
Sven

this is true of many non internal focus macro lenses, including the vaunted Nikkor 60 mm f2.8
--
pbase & dpreview supporter
Fuji forum member since 5/2001
http://www.pbase.com/artichoke

J-P. Scherrer said:

...the Exifs datas show that the focal length is NOT 90 mm. but 89
mm. (on my Fuji S2 Pro) !!!

Click to expand...

Yep, most macro lenses lose focal length.

CK