Question about D40 lenses

[ghost]

I really would like a D-SLR and the D40 is in my price range. I understand that the D40 needs AF lenses for auto focus which can be much more expensive and there is a smaller choice. I went to future shop and manual focus seems annoying at worst. I am used to P&S and I like auto focus. If I were to buy a new lens I would probly get a macro lens. I would use the kit lens for the bulk of my shots. I understand that the AF lenses are more expensive. Do you think it is worth it for the AF???

I was looking at this lens for macro stuff
http://www.henrys.com/webapp/wcs/sto...&itemID=120752

but compared to this
http://www.henrys.com/webapp/wcs/sto...&itemID=121601
is the auto focus really worth it? and I know more $$$ = +quality but dont have enough $$$ and it is just a hobby that I want to start.

sorry if this doesn't make sense as I am still trying to learn all the little things before I buy, if I do. Thanks in advance.

[erichlund]

I really would like a D-SLR and the D40 is in my price range. I understand that the D40 needs AF lenses for auto focus which can be much more expensive and there is a smaller choice. I went to future shop and manual focus seems annoying at worst. I am used to P&S and I like auto focus. If I were to buy a new lens I would probly get a macro lens. I would use the kit lens for the bulk of my shots. I understand that the AF lenses are more expensive. Do you think it is worth it for the AF???

I was looking at this lens for macro stuff
http://www.henrys.com/webapp/wcs/sto...&itemID=120752

but compared to this
http://www.henrys.com/webapp/wcs/sto...&itemID=121601
is the auto focus really worth it? and I know more $$$ = +quality but dont have enough $$$ and it is just a hobby that I want to start.

sorry if this doesn't make sense as I am still trying to learn all the little things before I buy, if I do. Thanks in advance.

The D40 does not have as bright a viewfinder as my D200 or the D80. For that reason, you will strongly appreciate autofocus lenses. However, you have to look for AF-S, not AF. AF lenses auto-focus if the camera has a focus motor. The D40 does not. AF-S lenses have the motor built into the lens. In addition to Nikkor lenses by Nikon, you can autofocus with Sigma HSM lenses. I think Tamron and Tokina also have some options, but I haven't researched this, as my D200 has a focus motor.

With the Sigma lenses, you have to be careful that you are looking at the right lens. The Sigma you picked does not have the HSM motor, so it will not autofocus. There is an equivalent lens with the HSM motor, but most people would recommend the 18-50 f2.8 HSM version.

The D40 usually comes as a kit. I don't know if you can get it as body only. If not, you are going to get a lens like the Nikkor 18-55 AF-S, so that takes care of your 18-50 range anyway. If so, do you really want to duplicate that range with the Sigma?

If macro is more important than a telephoto for you, then you really have only a few AF-S capable options. There is the Nikkor AF-S 105mm f2.8 VR micro (micro is Nikon's name for macro, because not all micros go to 1:1, so they don't call them macro). In Sigma, you will have to have a combo lens, and it looks like they haven't released any HSM versions on their website yet. They may be available, I just don't know. If that's the case, then if you can find the camera body only, you may be best off with the Sigma 18-50 f2.8 HSM Macro. Then you can pick up the Nikkor AF-S 55-200 VR (cheap and good) and you will have a very nice starting kit. Make sure you get the VR version. The non-VR version isn't a very good lens.

[ghost]

WOW! that answered all of my questions! the only reason I chose those two lenses is there min focus distance. If the kit lens has a decent focus distance than I will be fine. i think. that helped a lot and put me on the right track. and for that I thank you.

[Rooz]

the kit lens does not have adequate min focus distance for macro work. for that you will need the sigma 18-50mm f2.8 HSM Macro. this will give you AF and some macro capability, but not full 1:1 macro. sigma also make the 150mm HSM f2.8 Macro lens which i use and it is magnificent.

the other option is to get the d40 kit and whack some extension tubes on the kit lens. this will give you macro at a very cheap price.

[Prospero]

the kit lens does not have adequate min focus distance for macro work. for that you will need the sigma 18-50mm f2.8 HSM Macro. this will give you AF and some macro capability, but not full 1:1 macro. sigma also make the 150mm HSM f2.8 Macro lens which i use and it is magnificent.

the other option is to get the d40 kit and whack some extension tubes on the kit lens. this will give you macro at a very cheap price.

The kitlens is actually just a suitable for close-up work as the sigma 18-50mm f/2.8 HSM macro. The advantage of the Sigma is neglicable. The Sigma can reach a maximum reproduction ratio of 1:3, while the kitlens can do 1:3.2.

If the OP is looking for a lens to do regular shooting and close-up work with, I think the Sigma 17-70 f/2.8-4.5 HSM would be a better choice, as it can reach 1:2.3 as a maximum reproduction ratio.

[fionndruinne]

Although the 18-50mm f/2.8 has shallower DoF, which is usually desirable for macros.

[Prospero]

Although the 18-50mm f/2.8 has shallower DoF, which is usually desirable for macros.

The Sigma 17-70 at the maximum magnification actually has a shallower depth of field than the Sigma 18-50 at its maximum magnification, despite the difference in aperture. The focal length is more important in achieving a smaller depth of field than the aperture.

Also, for macro work the shallow depth of field is often not all that desirable. Generally, you will need to stop down beyond f/10 to get the whole subject in focus. The shallow DOF is sometimes nice for creative effects, but generally a longer DOF is prefered.

[fionndruinne]

So 70mm @ f/4.5 is shallower than 50mm @ f/2.8? Sounds odd to me. I know focal length has an effect, but that strong?

[Prospero]

So 70mm @ f/4.5 is shallower than 50mm @ f/2.8? Sounds odd to me. I know focal length has an effect, but that strong?

Yes, if the subject distance is the same (in this case the minimum focus distance of 20 cm), this is the case.

You can see why by looking at the formula for Depth of Field:



N = apperture, c = circle of confusion, f = focal length, s = subject distance

If you look at the exponents you will see that the focal length is most important in this equation as it is taken to the power of 2 in the numerator and to the power of 4 in the denominator.

If you fill in the values in DOFmaster.com you will also see that this is true.