Important Considerations When Buying a Lens

by Jim Zuckerman

The two photos shown below were both taken in St. Peter’s Basilica in the Vatican. Michaelangelo’s famous Pieta is behind protective glass and the other sculpture was in the open. No tripods were allowed inside the church, so the only thing I could do to get acceptably sharp pictures was to increase the ISO. As we all know, if the ISO is too high the image quality suffers. There is too much noise, or grain, and the sharpness of the subject is somewhat degraded as well. The diminished color saturation and contrast can be repaired in Photoshop, but the other problems can’t really be fixed.

There are two other factors that help put the odds in our favor in this kind of situation: Image stabilization (or in Nikon-speak 'vibration reduction') and a lens with a large maximum f/stop. IS (or VR) lenses were developed to address the issue of small movements that naturally occur when hand holding a lens, especially a heavy telephoto. Photos are normally blurred when slow shutter speeds are used unless you have this feature. A lens that is equipped with this type of technology enables you to take sharp pictures in low light environments with much slower shutter speeds than you would normally want to use. This makes a huge difference; in the case of shooting in St. Peter’s, it was the difference between getting the photos or not.

The maximum lens aperture is also critical. Fast lenses – meaning lenses that have large lens openings, like f/2.8 in a telephoto lens – let more light into the camera. The result is that the shutter speed can be faster. The photo of the Pieta was taken with a 70-200m f/2.8 telephoto with image stabilization. My shutter speed was 1/30th, which usually is considered to be an impossible setting to use for hand-holding a telephoto lens. For the other sculpture, I used an astonishing 1/10th of a second and it turned out tack sharp.

When you consider buying a lens, consider the factors carefully. Lenses with smaller maximum lens apertures are cheaper and lighter to carry. But – you will miss getting sharp pictures in many situations.

Comments

[geoff]

Hi Jim,
Very impressed with your photos I am pleased that you give the IS lenses a good write up as that is what I have. When you get to my age you need all the help you can get when not using a tripod and have a telephoto lens attached to the camera.
If I could take photos like yours I would be very satisfied
Regards
Geoff Butler

[Mary]

These shots are amazing, especially considering the shutter speed. Even with image stabilization shooting at the slow a speed and getting such great results is impressive.

[Sam]

Hi Jim. Thanks, this is really useful, I didnt realise you could get lenses that overcame this problem. I have a heavy telephoto lens (maximum aperture is only 4 though unfortunately) and unless I use a tripod I can only use this lens in very light conditions (thankfully this was the case when I was fortuanate enough to photograph a kookaburra the other day, I'm abotu to start the light and flash course with you so I will upload the photos).

[Harold Bonacquist]

Jim: One problem I face with my fast lens (Nikon 50mm f1.4) is limited depth of field, especially at close range. Your pix don't show this problem. How did you avoid this problem? Do more expensive lenses have better depths of field?

[Jim Zuckerman]

Hi Harold,

All lenses lose depth of field as you get closer to the subject. That's just the nature of optics. Your 50mm has a lot of depth of field, even at f/1.4, if you are 30 feet from the subject. That's how I got dof with these pictures -- I was fairly far away.

[Etan Lightsone]

Don't forget, you don't need a super expensive long telephoto zoom with f2.8 to enjoy low light photography.

The canon 50mm f1.8 is very cheap (around $70 dollars I think), and brighter than most expensive zooms.

You'll just have to use our feet to crop :)

[Patsy Sampson]

Jim, Is there an equivalent to the canon 50mm f1.8 for Nikon users? Unfortunately, I was cheap and got the Nikon 80-200mm f2.8 telephoto without stabilization.

This also raises the question about Nikon versus Canon graininess in general. Is there a study comparing these two?

[Amanda D. Austwick]

Great shots Jim. I'm glad you mentioned the canon f1.8 lens. I just bought a Canon Rebel XT, since I ususally use Nikon, but I need a smaller camera to carry around for opportunity shots. I have not bought any new lenses for it, but that one will be on my list.
Thanks for the info.

[Jeffrey]

Jim,
The pictures are great. As the others said, I agree I am glad you wrote an article on this issue. Prior to coming to BetterPhoto.com I was struggling on this same issue. I really wanted to buy the lower version of that lens (70-200 f/2.8 IS), the f/4. I went out and bought the f/4 took it home and did some test shots at dusk. I told myself I will never be completely happy, so I took it back and bought the f/2 with IS. Yes, my stomach really hurt for a day from sticker shock, but after that I have been very happy with the lens. Except for one factor, that is I have a Canon 20D so I have to deal with the 1.6 crop issue. Hopefully next year I can move up to a full frame. Thanks again, Jim.

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