Nikkor prime lenses

[Bernie Gunther]

More seriously, I think that the physical aperture (the actual hole the light passes through) will need to be bigger for say f2 with a longer focal length lens, so you're less likely to have compatibility problems with longer lenses moving from say a D200 to 'full-frame' than you are with short ones (edit: or to put it more clearly, manufacturers have more problems building shorter lenses for small-sensor cameras and that's why they have to build special designs for wideangle that often vignette like crazy on 'full-frame') but I don't really see where your socratic dialogue is heading ...

 

[boskysquelch]

but I don't really see where your socratic dialogue is heading ...

...it's a glitch I have when I see peeps bandy round digi, prime, xblahblahblah the focal length.

Sooooooooooooooo... an f1.4/50mm standard lens(ie made for 35mm film)...on a none full frame digi will be >f1.4 or <f1.4?

 

[Bernie Gunther]

Depends on what you think f1.4 actually is I guess.

If it's an absolute measure of the number of photons hitting the film/sensor thingy then it is different, 'cos the sensor is smaller. If it's just a ratio of the focal length and the size of the hole, then it's the same.

... I think.

 

[Bernie Gunther]

Ah ... hang on. You're on about depth of field aren't you? Hence the PC lens.

So for the same perspective, assuming I step backward to get it, I get more depth of field with the smaller sensor camera than with the full frame one ...

I still think the lens is f1.4 though, 'cos that's a property of the lens independent of the camera as far as I can see. A ratio of focal length and maximum 'hole size' (I'm sure there's a technical term for this).

It just acts differently in respect of the amount of light falling on the sensor (and hence presumably exposure), depth of field and maybe some other stuff I haven't thought of yet.

 

[boskysquelch]

okaies...then all that being said(iiiiiish )...what advantage is there in using a fast lens other than for focusing?...putting aside depth of field(for the sake of arguement, even so this is of great import too)... at f1.4-2.8 focus has to be of primary import..otherwise ain't no point using it.


and if anyone else wants to join in...don't introduce bokeh...coz it's as relevent as bukkaka photographically... unless the whole point of your image is to not inform...but distract to attract focii...then bokeh is kewlio...but not actually the point.


oooooooh...deja vu.

I've done this already... soz Bernie...prolly no point.

*goes back to listening to Derrick Jensen.

 

[Bernie Gunther]

Well, I can think of several photographic reasons why fast is nice, apart from 'equipment collector' reasons (which are still valid reasons in my book, 'cos I like precision machinery for itself and old high-end Nikon kit is certainly that.)

First I actually do like playing around with a very thin plane of focus and getting interesting swirly stuff to happen in the background. I dunno if that's bukakke or bokeh, but it's probably due to too many psychedelic drugs when young.

Second, a fast lens at a wide aperture seems to be easier to focus on a manual camera like the old F3 that I've been mostly using lately. Even on my very automated digital SLR it's actually quite handy to be able to see whether I agree with the computer about what should be in focus.

Third, in principle at least it makes it easier to work in spooky, shadowy conditions, which can be appealing, although I'd really like a much smaller camera that worked at much higher ISOs more for that type of thing. A fast lens does help a bit though.

 

[zenie]

Well advantage of using a fast lens would be that it's better for handholding in low light conditions when you aren't using external lights/flash. Or am I stating the obvious? (You can use a slower ISO because you're letting more light in and you won't get camera shake because you can still use a fast shutter speed)

At least that's why I want one anyway

 

[boskysquelch]

yes you are right*....lenses have probably changed since my day...sorry I fergot.


*if you intend to photograph details on one plane within a short distance...if you intend to photograph volume & depth there are easier and cheaper ways to do it which would afford you detailed pictures that are both guaranteed to be correctly exposed and correctly focused. I let others explain that if they want.

 

[cybertect]

And it won't work as on a full-frame body?

It's designed for a crop-sensor body, so the image circle is smaller than the diagonal of a full-size 35mm frame.

It's posible to mount it on a FF body, but you'd end up with the outer corners of the image quite black.

 

[Hocus Eye.]

The lens described in the OP is the NIKKOR 50mm f/1.4G

The following quote is from the Nikon Press Release as published in the DPReview review.

AF-S NIKKOR 50mm f/1.4G
The AF-S NIKKOR 50mm f/1.4G lens is a fast, fixed focal-length lens with normal picture angle when used with Nikon’s FX-format D-SLR cameras.

FX is the name for Nikon Full Frame format.

As to Bosky's question in post 32 my guess is that if the lens is used on a DX crop camera then the increased focal length which is gained is at the expense of lens speed, that is the aperture is reduced pro-rata to the increase in focal length. This is similar to what happens when you use a 2 times converter with a lens where you lose a stop worth of aperture.

Zenie is of course right in wanting a wide aperture ie. fast lens for hand holding in low light conditions where she doesn't want to use flash or lights. Some of the most interesting pictures are to be had using available light indoors or where the background light is weak giving an atmospheric mood that would be ruined with flash.

A wide angle lens probably does make focussing easier in that focussing is more critical. This is why you open up the aperture on an enlarger for focussing and then stop down before making the exposure. This should make little difference with automatic focussing systems though.

 

[cybertect]

One other advantage of wide apertures that nobody's mentioned - you don't see the dust on your sensor

 

[boskysquelch]

I <3 Ken

http://www.kenrockwell.com/tech/lens-sharpness.htm

 

[stowpirate]

http://www.kenrockwell.com/tech/lens-sharpness.htm

Anarchist

 

[boskysquelch]

Anarchist

resistance is fertile!