Worth getting fast lens if it has to be stopped down?

[PolarBear1973]

Hi all,

Been doing a lot of pictures of cycling (outdoor) lately. I've been using a D90 with the 18-105mm lens. I usually stop the lens down to f/8 in order to get the whole rider, or two riders in focus. My question is this: is it worth buying a fast lens (like the 70-200 VR), if I'm just going to be stopping it down to f/8? Would the 70-200 transmit more light at f/8 at 105mm than my 18-105mm lens at f/8?

The VR is not important to me. The AF-S is though.

Thanks,
Bri

[GadgetRick]

Well, the faster glass is (typically) a better lens all things being equal. So you should get a better picture (at equivalent f stop) with less distortions in the corners, edges, etc.

The lens with faster glass may also be built better as well. So it may not break as easily.

[rediguana]

At the same focal length, and the same aperture, they should be transmitting the same amount of light. So there probably isn't any benefit to be gained from a faster lens. A faster lens is only a benefit if you use it opened up.

[OsmosisStudios]

The lenses you mention fulfill very different roles, and thats why it may not be of use to you. If youre shooting at f/8, the only real differences you'll see are in distortion, flare, CA, colour, rendition, contrast, etc.

The reason the 70-200 f/2.8 is so popular is that you can use it a full 2 stops better at 105 than the 18-105 (f/2.8 vs f/5.6). Even if youre not using it wide open, 1 stop is better than nothing. And you get all the advantages i mention above.

[vandergus]

If you're you're just shooting at f/8 you'll be hard pressed to see the differences between the two lenses. All lenses perform well in normal conditions. You may the premium when you want to shoot in more diffifult conditions. That could mean low light, harsh light, high contrast, hazardous environment, really long or really short focal lengths, etc. Bottom line, if you're happy with the image quality you're getting with your current lens, there's no need to upgrade.

[LoveDSLR]

You may get faster focus lock with the 70-200's AF-S at f/2.8 (even when you shoot at f/8).

[PolarBear1973]

Thanks for the replies. That really clears things up.

[kirbinster]

Well all I can tell you is that pictures taken with my Nikon 70-200 f/2.8 are much sharper than similar pictures taken in the overlapping ranges from my 18-200, 55-200, or 70-300 lenses. The glass is just better.