Nikon 105mm f2.8 macro lens isn't f2.8!!!

[Trenton Romulox]

I'm curious on how the new 60mm macro is.

Yeah, same here. You seen it in stock anywhere? I check B&H every day. I can't wait to get one.

 

[Sw1tchFX]

Yeah, same here. You seen it in stock anywhere? I check B&H every day. I can't wait to get one.

Haven't checked, don't really need one.

 

[Garbz]

BTW this is why I recommend to all to buy the one YOU have instead of the 105 VR version... Yours doesn't have this autofocus defect, and VR doesn't work very well at macro distances anyway.

Sorry misread. Thought you meant the old non-VR one hunted. I haven't used the VR enough to form an opinion on it. Will retreat to my cave now.

 

[TamiyaGuy]

Here's another way of explaining it.

F-number is focal length divided by the diameter of the aperture (in fact the entrance pupil, but let's ignore that for now). A 105 mm f/2.8 lens has an aperture of 105/2.8 = 37.5 mm diameter.

As you focus more closely, a simple lens would have to move further away from the sensor/film. At 1:1 a simple lens would be twice as far from the sensor/film as it would be when focused at infinity. At infinity the simple lens would be one focal length from the sensor/film. At 1:1 the simple lens will be two focal lengths from the sensor/film - ie 210 mm in this case.

The f-number is now 210/37.5 = 5.6.

Because your Micro-Nikkor is cleverly designed, it achieves f/4.8 at 1:1 instead of f/5.6.

Best,
Helen

Thanks so much, it all maes sense now! I can kind of see why Nikon made the lens like that. Guess I'll have to do a bit more research before buying a macro. Still annoying, but what are you gonna do?

And to Sabbath: Thanks for the info. Interesting that it hunts all the way up to the D80. What I can't understand is why it's so fast! For example, my current lens very rarely hunts, but when it does (i.e. when I focus with the lens cap on ), it takes a good 2-3 seconds for it to cycle to infinity and back. On the 105, it takes less than a second!

Well, yet again, thanks ever so much to everyone who helped me. I've learnt a lot, and I'll take all of your thoughts into consideration when I come to buy.

P.S. What is all of this talk about a new 60mm macro? Do you mean something like this? Or that with VR? I might try it out...

 

[Garbz]

Forget annoying. There are practical issues too. At 1:1 f/5 the usable depth of field is literally less than 1mm. Even if you did have an f/2.8 @ 1:1 lens I doubt anyone would ever use it wide open.

 

[TamiyaGuy]

Forget annoying. There are practical issues too. At 1:1 f/5 the usable depth of field is literally less than 1mm. Even if you did have an f/2.8 @ 1:1 lens I doubt anyone would ever use it wide open.

Yeah, I do get that, but I always think it's better to have a feature and not use that to not have a feature and need it. I was thinking more about shutter speed than DOF.

Well, seeing as there is so damn much to take inot consideration, does anyone have a particular recommendation for a mid-range, fairly cheap macro lens? I think I'll try the 60mm Nikon, but what about the 90mm Sigma? I've been hearing good things about this. Is it worth it? Yet again, I'll test the lenses out, but if I could get a recommendation, that would be great.

Thanks!!!

 

[Helen B]

...I can kind of see why Nikon made the lens like that. Guess I'll have to do a bit more research before buying a macro. Still annoying, but what are you gonna do?

You might have some difficulty finding an f/2.8 lens that is f/2.8 at infinity and at 1:1 without the use of supplementary lenses. As I explained, most of them are f/2.8 at infinity and f/5.6 at 1:1.

If you are considering the 60 mm AF-S I'd be inclined to wait for a few reviews.

Best,
Helen

 

[TamiyaGuy]

Well, if the 105mm VR is anything to go by, I would get the 60 in an instant... if it was cheaper .

Are there any 3rd party macro lenses that will autofocus on the D40? I know HSM on a Sigma means it will, but what about Tamron or Tokina? And are they worth it? I'm looking for the lens to be anything between 60 and 105mm, really.

Thanks!!!