New 50mm/F1.8 Prime Lens

Just got this yesterday and took some test pictures. This is a prime lens, meaning the focal length is fixed. Instead of zooming in or out you move your body closer or farther away from the subject. Also, this is a Nikon AF lens. It autofocuses on older Nikon bodies and current models like the D50 and D80, but on my D40 it doesn’t autofocus. I have to focus manually. (LATER: see the update at the end of this post for a useful tip.)

So, why did I buy a lens that won’t autofocus and won’t zoom? Couple reasons. The reduction in moving parts helps make it sharp and rugged. This has the reputation of being one of Nikon’s sharpest lenses, while also being one of the cheapest. (I paid $110 here. As lenses go that’s cheap.) It also gives great contrast and I hope I can use it for some seated portrait work I’ll be doing for press releases. With the big aperture and a short shutter speed you can set a shallow depth of field that makes the subject sharp and the background blurry:

As long as I’m throwing out fifty cent photography terms, I’ll mention that 50mm is what’s known as a normal lens. A 50mm focal length lens provides the same angle of view as the human eye. So when used on a 35mm film camera or a digital camera with a full frame sensor what you see with your eye is basically what you’ll see through the camera’s viewfinder. The image in the viewfinder won’t be significiantly bigger or smaller than what you see with the naked eye. (For the vast majority of digital cameras with less than full frame sensors the DSLR crop factor comes into play. For Nikons the crop factor is 1.5, meaning the 50mm lens on a D40 will have the same angle of view as a 75mm lens. For Canons the crop factor is 1.6.)

This is also an amazingly bright lens (what photographers call a fast lens, because it allows you to use fast shutter speeds). F1.8 is a huge aperture. Like shotgun gauges, bigger apertures have smaller numbers. The kit lens that came with the D40 is F3.5 at the 18mm end and F5.6 at the 55mm end.

I was hoping Io take indoor pictures without using a flash, or using very little. Playing around with it tonight I had mixed luck in low light indoors. The kit lens actually seemed to do a little better closeup, but it’s entirely possible I don’t know what I’m doing. Any tips?

LATER: I was interpreting the blurry results in low light to mean that the shutter was open too long. Now I’m inclined to think I was just doing a stinky job of manually focusing the lens. Here’s something I learned tonight from Ken Rockwell. My Nikon D40 won’t autofocus this lens, but the focus meter does work with it and all (most?) AF lenses. As you adjust the focus manually look for the focus light in the viewfinder (it’s on the far left bottom on a D40 viewfinder). When it lights up the lens is focused. That’s an enormous aid in focusing AF lenses. I was eyeballing the focus and in low light conditions that didn’t always work so well.

Tags: d40

7 Comments to New 50mm/F1.8 Prime Lens

swanky
April 3, 2008

Have you tried tungsten film? Indoors, with normal light, it balances out the yellows of the light. It’s a nice effect. Of course, your camera may auto white balance, or you can use Photoshop. But for shooting people indoors under normal light, I like it a lot. It’s what they use in movie cameras.

Also, you probably will want to use some lighting to do portraits indoors. You get stuck with low light and you have to open it up so far with even 200 speed film that you loose depth of field control etc. You can use big 500 watt halogen work lights with paper over them as a filter to not blind. I have been using CFL bulbs I get at the Big Box stores that are 5600K lights. They are harder to find now with so many CFLs out there, but they make great white light cheap. Put them in a standard clip on work light. I think they are called Day Light lights and you’ll know by that Kelvin rating. Less blinding than halogens and a LOT cooler in the room.

Les Jones
April 3, 2008

I’ll give the Tungsten setting a try. I’m also experimenting with using a custom white balance set on whatever I can find that’s solid white. Need to buy a gray card.

The indoor portrait thing is going to be a learning experience. I don’t have any budget to do it with, so I’m going to have to get creative. I’m going to experiment with natural lighting in front of a big window and using a reflector for fill. I’ve got a bounceable speedlight and a sto-fen on the way that may or may not be helpful.

The worklights sound interesting. I was looking at designs for homemade whiteboxes using little $3 worklights. I’ve actually got one in a box in the attic from when I used it as a warming lamp for a pet scorpion.

jeff
April 3, 2008

For head-shoulders shots, I would go with a 105mm lense. For head-waste, try an 85mm.

Use a tripod.

Bounce a small flash off the back wall to separate the wall from the foreground.

Don’t forget the ceiling as a bounce card.

People tend to have one eye larger than the other. Look closely. Angle the person so the larger eye is further from the camera.

If using the sun, don’t forget about the color cast made by early / late sun.

Tungsten is inexpensive, but it gets hot quickly. Using tungsten with sun and tungsten white balance will cause blue cast to sunlight.

If you have two light sources of equal output, You can use your f-stops as distances to provide some modeling to your subject. For instance, place one light at 5.6 feet and the other at 8 feet. The closer light will provide twice as much light as the farther light on the subject. Same for 8 feet and 11 feet.

Les Jones
April 3, 2008

Cool. Thanks for the tips. You’re right that the 50mm is kinda short for portrait work, but I’m hoping it will work.

fletch
April 4, 2008

very cool. Canon lens users also say the fixed focal length lenses are by far the sharpest. I don’t use autofocus on most of my shots anyway because I don’t like the constant movement and the searching. If you shoot RAW mode you can set and customize the white balance to your heart’s content in the raw converter software and try different settings on the same raw image.

Les Jones
July 21, 2008

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