Question about aperture on a macro lens.

Kyle D

Hi Everyone,

I have a quick question about the aperture on a macro lens. I just bought my first macro lens :barband have never used one before. I believe it is the first generation of the Tamron SP 90mm AF f/2.8 macro lens, the one before they made them Di. I bought it from the Henry's eBay store for a great price. However, when I mount it on my D50, the largest aperture I can get is f/3. I was wondering if that was ok/acceptable?

Also, I noticed when I was picking up and mounting the lens, it sounded like there were tiny little loose pieces of metal rattling around inside the lens mount or near the lens mount. I don't know of any other/better way to describe it than that.

So, should I be worried about both of these? The ad on eBay stated it was in perfect mechanical condition and it appears to AF perfectly fine and the two quick hand held shots I fired off seem to look ok. I will give it a more thorough test maybe tonight or tomorrow morning.

ziggy53

I have that lens (the non-"Di") in the Canon mount.

Mine does register an f2.8, again on Canon cameras. What does your EXIF read in the image when the aperture is wide open?

In mine, there a very light "ticking" when I gently shake the lens. It does not sound like it is "floating" around inside the lens however. It almost sounds like a light piece of metal not completely secured by a screw. I regard it as perfectly normal. (It's probably part of the manual/auto focus clutch.)

Kyle D

ziggy53 wrote:

I have that lens (the non-"Di") in the Canon mount.

Mine does register an f2.8, again on Canon cameras. What does your EXIF read in the image when the aperture is wide open?

In mine, there a very light "ticking" when I gently shake the lens. It does not sound like it is "floating" around inside the lens however. It almost sounds like a light piece of metal not completely secured by a screw. I regard it as perfectly normal. (It's probably part of the manual/auto focus clutch.)

I will have to check the exif when I get home and fire off some more test images.

Your description of the sound is perfect. Ok, I guess I won't be too worried about it.

Thanks

Kyle D

I shot some new test frames tonight and according to the exif on the camera and in Capture NX 2, the largest aperture is f/3. Should I be worried about this/try and return it?

ziggy53

Kyle D wrote:

I shot some new test frames tonight and according to the exif on the camera and in Capture NX 2, the largest aperture is f/3. Should I be worried about this/try and return it?

I suggest trying the lens on another Nikon camera. If the same problem occurs on another camera then yes, I think there is a problem with the lens.

If another camera allows f2.8 operation and yours does not, then you have a decision to make about whether to keep the lens.

gowiththeflow

Just a thought here... have you tried it with the focus @ infinity?

I have the 85mm Micro, and it starts raising the f-stop from 3.5 as soon as you get to the 1:10 reproduction mark, which is pretty close to infinity.

Kyle D

I just tried it in manual focus mode, the aperture still won't go below 3. But, I noticed that the focus scale stops at L (the middle line at the bottom of the window) and doesn't get to infinity. Does this mean that it isn't able to focus to infinity?

Also, when I'm out today I'll pop into a camera store and see if I can try it out on a D90 or a D300.

ziggy53

Kyle D wrote:

I just tried it in manual focus mode, the aperture still won't go below 3. But, I noticed that the focus scale stops at L (the middle line at the bottom of the window) and doesn't get to infinity. Does this mean that it isn't able to focus to infinity?

Also, when I'm out today I'll pop into a camera store and see if I can try it out on a D90 or a D300.

Can you move the mechanical limit switch to the "Full" position? See if that solves the aperture problem as well.

Kyle D

So, after popping into Henry's today and talking with them, it turns out I was reading the focus scale incorrectly and it does focus to infinity. I can freely turn the focus limit switch and it doesn't affect the inability to go to f/2.8. However, after trying it on a D3000, D5000, D90, D300s, D700, D3, D3x, and even a pair of D2H's, my D50 was the only one incapable of getting it to go to f/2.8. It stubbornly stayed at f/3.0.

Fortunately Henry's offers a 90-day warranty on their used gear so I might have to take advantage of that. The other option is I just return it because it doesn't as advertised on my camera.

time2smile

I have a Cosina F2.8 lens that on my D50 only goes to F3. It does f2.8 on my D90. Took many pics with D50, never a problem.

Kyle D

Any idea why it only went to f/3 on the D50?

ziggy53

The Tamron 90mm, f2.8 macro is still a great lens. I suggest that the difference between f2.8 and f3 is not enough to cause any trouble. If anything you should return the Nikon D50 since it seems to be the problem (and I'm joking.)

If the lens is otherwise working for you, embrace the positives and consider keeping the lens.

time2smile

Kyle D wrote:

Any idea why it only went to f/3 on the D50?

No, at the time I thought it was just a cheap lens, I think I paid $100 brand new its the Cosina 28-105 F2.8-3.8, used it for a season to do swimming photos, slammed hard when focus wasnt found, with the D90 it doesnt slam as much either.
Like Ziggy said if it works for you and was a great price....
If we report the problem to Nikon, maybe they will admitt it was aflaw, and dive us D3 for our trouble...

Kyle D

ziggy53 wrote:

The Tamron 90mm, f2.8 macro is still a great lens. I suggest that the difference between f2.8 and f3 is not enough to cause any trouble. If anything you should return the Nikon D50 since it seems to be the problem (and I'm joking.)

If the lens is otherwise working for you, embrace the positives and consider keeping the lens.

Maybe they'll exchange it for a D300s for all my "pain and suffering"?

I think I'll still get in contact with Henry's eBay department and see what they say, but I do want to play with this lens more.

rookieshooter

That is typical behavior for a macro lens. The Nikon f2.8 macro does about 3.2 or so in macro mode, but you really don't want to shoot wide open in that mode anyway due to very shallow DOF. But don't go above f16 or so or you will lose sharpness. I shot at f52 once

Kyle D

rookieshooter wrote:

That is typical behavior for a macro lens. The Nikon f2.8 macro does about 3.2 or so in macro mode, but you really don't want to shoot wide open in that mode anyway due to very shallow DOF. But don't go above f16 or so or you will lose sharpness. I shot at f52 once

From my understanding, this Tamron is just like the Nikon macro in that it is a variable aperture. So at infinity it should be able to do an aperture of f/2.8 and as you focus closer the aperture shrinks.

I still can't figure out as to why this won't do f/2.8 on my D50 but on every other Nikon I've tried it on it will do it. Hmm...strange...very strange...However, I think I might just live with it or possibly send it away to be "fixed".

ziggy53

Kyle D wrote:

From my understanding, this Tamron is just like the Nikon macro in that it is a variable aperture. So at infinity it should be able to do an aperture of f/2.8 and as you focus closer the aperture shrinks.

I still can't figure out as to why this won't do f/2.8 on my D50 but on every other Nikon I've tried it on it will do it. Hmm...strange...very strange...However, I think I might just live with it or possibly send it away to be "fixed".

Some macro lenses extend so far out that they enlarge the image circle and reduce the amout of light per unit area as a result. The varying reportage of the aperture is not a change in the physical aperture, but just a reflection of a loss of efficiency. If you use an extension tube on a lens to reduce the close focus capability of the lens, you would have a similar aperture correction.

The f3 maximum aperture you are seeing is probably a result of the D50 body misintrepreting the aperture data from the lens, a "reporting" error if you will. Since the difference between an f2.8 and f3 is about a quarter of a stop, it is unlikely to be any significant problem in actual shooting. Heck, it might even be a more accurate representation of the true aperture. (Many aperture ratings are rounded and "fudged" to produce a more marketing friendly number.)

I doubt that there is anything wrong with the lens or anything that can be corrected. If the lens is working for you, relax and enjoy it for what it is. It is a very high quality optic, IMO, and a genuine value in true macro lenses.

Besides, when you do upgrade bodies, it sounds like you will see the f2.8 reportage that you desire.

Kyle D

ziggy53 wrote:

It is a very high quality optic, IMO, and a genuine value in true macro lenses.

You are not kidding when you say it is a genuine value! I picked it up for $200 CAD! Personally, I think that was quite a steal.

Now the real problem is finding time to play with it!