50mm Prime Lens Advice for my D7000

[inkista]

I see a noticeable difference in field of view between FF and APS-C lenses on my 1.7 crop DSLR's. Specifically, APS-C 17-70mm zoom @ 70mm and a FF 70mm macro lens; also APS-C 17-70mm zoom @ 50mm and a FF 50mm macro lens.

Any ideas why, anybody?

Because your 17-70 might not actually reach 70? If this is the Sigma 17-70/2.8, you're not the first one to notice that 70mm looks shorter than 70mm on other lenses.

[BigEater]

I see a noticeable difference in field of view between FF and APS-C lenses on my 1.7 crop DSLR's. Specifically, APS-C 17-70mm zoom @ 70mm and a FF 70mm macro lens; also APS-C 17-70mm zoom @ 50mm and a FF 50mm macro lens.

Any ideas why, anybody?

Part of it is that a lot of lens makers round up or down when they tell you the focal length of the lens. And there's another issue which is called by the peculiar name of "focus breathing." With lots of lenses the image size changes as you focus at different distances. Don't feel bad, it happens at all price levels of lenses. The $2200 Nikon 70-200 is famous for this; at close range it acts like a 134mm lens according to one tester while at infinity it got to about 192mm. You can buy lenses that don't have this issue but they'll have other tradeoffs.

[charzes44]

For those members who are interested in street photography, there are some informative free ebooks on the subject here:

http://www.thomasleuthard.com/books.html

Charles

[ajohnw]

I had a look at some test results on here for what they are worth as 35mm and apertures like that are outside my experience. Going on these I would go for the F1.8 for it's more even performance. Slightly more distortion than the F2 but I feel that the more even resolution makes up for that.

http://www.photozone.de/nikon--nikko...3518dx?start=1

50mm folklaw which I think is broadly correct goes F1.2 a step too far for desperate people, F1.8 /F2 the budget lens, F1.4 not that good wide open but a nice even performance say F4 and slower. Where out of focus backgrounds are needed with the lens set faster or even wide open the central resolution is good enough for the subjects that may benefit from it. Looking at Nikon tests on various Nikon cameras on the same site these aspects seem to still be worth considering to me.

John
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[flashback]

John,
Thanks for the link. Quite technical but I've bookmarked it as I suspect down the road it will be a hand reference.

Thanks to all for contributing, now I simply need to decide and purchase.
(Obviously should anyone else choose to offer suggestions and comments those too will be greatly appreciated.)

Jack

[ajohnw]

This site can be useful too. Similar but no numbers and covers a number of lenses.

http://www.ephotozine.com/article/ni...s-review-16650

John
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[Colin Southern]

But at times he is well known for confusing opinion for fact; so his reviews are a bit hit and miss. He can be an amusing read, and I find he is bang on about half the time, as for the other half...

I agree.

I like Ken - he's always thought-provoking, but I think people need to consider what he says in the context of whether or not it's good advice FOR THEM.

At least the guy has a personality, which is more than I can say for most other review writers (not all, just most).

[William W]

I think that before you buy any Prime Lens that you need to think more about what is the most suitable FoV for what you want to achieve.

To do this you first need to broadly define what "Street Photography" is going to mean for you and the way you will work.

If you have a zoom lens - a kit zoom lens is very useful - then set it and then TAPE IT at about 24mm; and then 35mm; and then 50mm and use it at that FL for one week each and take three weeks worth of your "Street Photography".

I think that you don't yet realize how very important the choice of FL will be to you in this endeavour.

WW

[flashback]

William,
Thanks for your reply. Actually I was pretty much doing what you suggested (various FL) but I was working also with the lens pre-focused (@ ~20ft). Problem is my kit lens (18-105) isn't that fast in low light. For what it's worth I've decided on the DX 1.8 35mm. I feel it's a decent enough lens to allow me to learn the craft (@< $200 it gets very good reviews and is a good place to start).

[William W]

Thanks for coming back.

I definitely think that a 35mm Lens is a much better choice for you to start with, than using a 50mm lens.

If you like getting around at night, do not be afraid to pump the ISO to 3200 or 6400 on your D7000. The trick is to NOT underexpose, not even by a whisker.

(Just a guess) - I expect that using the lens at F/2.2 you'll notice a difference than using it wide open at F/1.8.

At F/2.2 and ISO3200~6400 you should have enough Shutter Speed to have a lot of fun at night-time, out and about.

Good luck with it.

WW

[ajohnw]

If the 35 is a decent lens and it appears to be it will crop to 50mm equiv easily for pc screen use. In fact it will probably double that way.

John
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[flashback]

I'll let you all know. I'm going to get the 35mm tomorrow.
FWIW I purchase at 17th Street Photo, much smaller than Adorama but I feel the service is much more personal and the people much more personable. Just saying, they're another option...