Lense spec confusion

tlittleton

OK...so I'm trying to decide which lense I want to get for a first lense. I am thinking about getting the 50mm f/1.8 since that seems to me to be a good basic lense. But I hear any people going with the f/1.4. Is there really that big of a difference between the two to justify the extra cost?

Also, when looking at these lenses, is the aperture fixed, or is f/1.4 the widest aperture that the 50mm f/1.4 will do?

And last (well for the moment anyway...give me time...), there's the focal length conversion. Is the fact that the camera has a 1.6x magnification a good thing when buying a lense, are there lenses that correct for this?

I hate asking so many questions at a time, but there are just so many lenses out there that it's kind of hard to decide where to start.


So many toys, so little money......:D

mercphoto

tlittleton wrote:

OK...so I'm trying to decide which lense I want to get for a first lense. I am thinking about getting the 50mm f/1.8 since that seems to me to be a good basic lense. But I hear any people going with the f/1.4. Is there really that big of a difference between the two to justify the extra cost?

The 1.4 version is built more sturdy, has a faster focus mechanism, and has more blades in the aperture. The more blades thing has a positive impact on the appearance of the bokeh, or background highlight blurring. Due to more blades things look more circular. With fewer blades things look more like pentagons.

Also, when looking at these lenses, is the aperture fixed, or is f/1.4 the widest aperture that the 50mm f/1.4 will do?

Lenses are rated with the max aperture.

And last (well for the moment anyway...give me time...), there's the focal length conversion. Is the fact that the camera has a 1.6x magnification a good thing when buying a lense, are there lenses that correct for this?

You cannot "correct" for this. Focal length is focal length and has nothing to do with the size of the sensor or film being used. Its purely a matter of the physics in how the lens is constructed. Note that while 50mm is a "standard" lens for 35mm film, the same is not true of medium format film. For medium format a different focal length has the same FOV, and nobody complains about that.

Only digital people "complain" about the crop factor it seems. As to whether the crop factor is "good" or not depends on your needs. If you want to shoot wide angle it can be a bad thing. If you want to shoot telephoto its a good thing. If there was one other good thing, it would be the fact the crop factor takes a slice of the image from more of the center of the lens, which is where the sweet spot should be. If a lens has a failing, it is usually on the fringes.

wxwax

Hiya! I think you should do some Googling to understand how SLR lenses work.

The aperature size given for a prime lens is the max it will open up. It is not fixed. If you plan to shoot in dark places, then the f1.4 is very helpful.

Most first-timers gets zooms instead of primes, because they offer far more flexibility. Expensive zooms have the same max aperature all the way through the zoom range. Slightly less expensive zooms will shrink the max aperature as you zoom out, so you'll get two f-stop numbers - one for zoomed in, and one for zoomed out.

Having said that, there's a lot to be said for learning how to shoot with a prime. It will force you to learn composition by moving your feet instead of twiddling your fingers on a zoom.

50mm is considered the 'classic' lens for learning. With your camera's crop factor, a 35mm lens is the closest equivalent. Again, you can go expensive or slightly cheaper.

Your camera's crop factor is what it is. It gives you more apparent range on long lenses, and makes wide lenses less wide.

Good luck! Let us know what you get, and show us yer pics.

Shay Stephens

Get the 50mm f/1.8, it's not called the plastic fantastic for nothing you know

I have one, and regularly use it in my professional work. It is small, light, bright, fast, is a great portrait lens, it's cheap, and it does macros.

I have been more than happy with it, and would buy it again.

Now as far as crop factor, it's good if you shoot telephoto, it can be a hindrance if you shoot wide angle. You get more bang out of your buck with telephoto, as a 100mm lens will give you the equivalent of 160mm. That's like getting a bottle of shampoo with 60% more, free.

But if you are shooting wide angle, say 28mm, you need to actually shoot wider, like 18mm to get the equivalent of 28mm. That is why I have to use the 16-35mm lens in order to get the wide angle look I want instead of getting a 28mm lens which would only give me the equivalent of 45mm.

Khaos

Shay Stephens wrote:

That is why I have to use the 16-366 lens in order to get the wide angle look QUOTE]

Whats that weigh, about 10 pounds?

Shay Stephens

Woops, I meant 16-35mm, hehehe, I edited the post. Thank you

Khaos wrote:

Shay Stephens wrote:

That is why I have to use the 16-366 lens in order to get the wide angle look QUOTE]

Whats that weigh, about 10 pounds?

wxwax

Khaos wrote:

Whats that weigh, about 10 pounds?