I have been shopping around for a prime lens for my Nikon D50. I noticed that the 1.8 is hundreds of dollars cheaper than the 1.4 AF-S. What will I gain for that cost difference? Is it really noticeable?
It's an extra two-thirds of an f-stop, with all that comes with it:
- Narrower depth of field (perhaps marginal in comparison to the f/1,8)
- Brighter viewfinder; great in low-light situations
- Might be the difference between getting the shot or not, also in low-light situations
- Lenses tend to get sharper when stopped down. At f/1,8 the f/1,4 lens is stopped down two-thirds of a stop, while the f/1,8 is wide open. I don't know if there is any actual difference in sharpness between the lenses here, but I would assume that the f/1,4 is sharper at f/1,8 than the f/1,8 lens.
Is it worth the price difference? Only you can tell...
Here's the Thom Hogan review: http://bythom.com/Nikkor50AF-Slensreview.htm
His take is: yes, the f/1.4 is somewhat better, but not by a whole lot, so save your money unless you really do need the extra 2/3 stop. Consider boosting the ISO by a stop instead (and you should be ignoring the pixel-peepers and their 100% crop noise tests anyway).
Also note that the f/1.8 D does not have an internal focusing motor and thus is not compatible with some bodies. I don't recall if the D50 is such a body, but check this.
I wouldn't worry about depth of field, because it makes focusing that much more critical and also having too narrow DOF is a much more common technical error than too deep DOF.
Assuming this is a 50mm lens than for DOF the difference would be:
- 50mm, f/1.4 w/ subject 10 feet away = 7.8"
- 50mm, f/1.8 w/ subject 10 feet away = 9.7"
- You can check different focal lengths/distances here: http://www.dofmaster.com/dofjs.html
As far as shutter speed goes, f/1.8 to f/1.4 is a half-stop, so:
- if your shutter speed was 1/30 at f/1.8, it'd be 1/45 at f/1.4.
- if your shutter speed was 1/100 at f/1.8, id be 1/150" at f/1.4
- You can calculate other shutter speeds by just multiplying the shutter speed at f/1.8 by 1.5 to get the shutter speed at f/1.4. Or divide to go the other way. (Full stops double as the aperture value gets lower, so a half stop is 1.5X. Just divide to go the other way.)
Yes, there is a noticeable difference between the 1.8 and 1.4. My thoughts on the subject in a few bullet points
- Ignore the light difference, there are more significant differences between those lenses
- The focus on the 1.4 AF-S is much faster and more accurate
- The focus on the 1.8 does quite a bit of hunting in low light
- Image quality is also better on 1.4 AF-S but my experience here is a bit limited. I have only used that lens in the shop.
I usually shoot the 24-70 2.8 and when I occasionally switch to the 50 1.8 it is always a bit frustrating. Once I wanted to avoid intimidating kids during a birthday party and went with the prime. I regretted it so much when the focus couldn't keep up with fast moving non-cooperating objects. If you can afford the 1.4 go for it, I regret that I didn't and I will as soon as I can afford it.
You can compare the technical results from reviews such as those at photozone. It is interesting to see that the AF 50/1.8 D has less distortion than the AF-S 50/1.4 G. The centre resolution of the f/1.8 is also higher at all apertures, although the f/1.4 is more consistent out to the borders.
However you have to work out what you want from such a lens and at what apertures you expect to use it.
Also consider that the price difference reflects the design & manufacturing cost rather than the value or quality: it is that much more difficult to make an f/1.4 lens.
Yes, but until you master the 1.8 lens I wouldn't recommend spending the money on the 1.4. The wider the lens the more precisely you have to focus to get good results. I've taken photos of a person's face where the eyes were in focus but the nose is blurry with the 1.8. So get the 1.8, and get good at manually focusing it. Even with AF-S on the D50 you will want to manually focus a lot to get really good results with this lens.
Heh, that's the same camera I use!
I don't have a nifty-fifty, but my understanding is that you don't get even a full extra stop when moving from 1.8 to 1.4. Also, I've read that the 1.4 version introduces more distortion. Unless you really need the best max. aperture, save your money and get the 1.8 version.
Besides the DOF questions, i'd like to point out that the effective focal length of a 50mm FX lens when used on a DX camera (like the D50), will be about 70 or 75mm. Make sure you consider that when thinking about this lens. I happen to like it, as the lens feels a little like a "portrait" lens, and the DOF control is very nice. Buying the Nikon FX 35mm lens puts you at about 50mm on a DX camera, but it also has a minimum aperture of f/2, thus different DOF characteristics:
some of the pictures on my web-site, like this one:
were shot with the 50mm 1.4 on a Nikon D90.
It's quite a bit of difference if you are shooting indoors or at night...which is why most people get it. For daylight in portraits it won't be as much. I'd rather have a 35mm 1.4 but it's way too expensive for me. I shoot on DX with a sigma 30mm 1.4 for a normal lens and a nikon 50mm 1.8g for portraits. If you are on FX, get the 50mm 1.4g and the 85 1.8g for portraits. The sigma 30mm 1.4 is supposed to be equivalent to the 50mm 1.4g... Nikon doesn't make a 1.4 for dx, b/c they want you to upgrade to FX...Same thing at other lengths. They don't make a 24mm 1.8, only the super expensive 24mm 1.4. So it's either sigma 1.8 or nikon 2.8 at that length.
Nikon sells 2 versions of most their prime lenses. The 'G' version contain an internal engine that "enable high-speed, extremely accurate and super quiet autofocusing" according to Nikon. The 'D' version are more simple (the engine is in the DSLR) and usually cheaper.
Also, it seems that most of the new "low end" lenses (IE 1.8 G) are for DX sensors only.