The eye of the camera - choose your lens wisely

Aug 18
15:37

2009

Linus Öhman

Linus Öhman

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How to choose lenses for your DSLR Lenses are the eye of the camera - and you don't want a lazy eye on your new digital camera. Sharpness, speed, focus, biggest aperture (smallest f-number), zoom length and technical gizmo's all come to play when choosing the perfect mate for a new dslr. Let's run down the list and see what it all means:

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How to choose lenses for your DSLR

Lenses are the eye of the camera - and you don't want a lazy eye on your new digital camera.
Sharpness, speed,The eye of the camera - choose your lens wisely Articles focus, biggest aperture (smallest f-number), zoom length and technical gizmo's all come to play when choosing the perfect mate for a new dslr. Let's run down the list and see what it all means:

Sharpness - The most important aspect of every lens. You want to cut diamonds - let the others try to make jewelery out of coal.
Speed - The performance of the lens as a whole, how fast the camera is able to auto-focus, how responsive it is to your tweaking and how well the buttons and rings are placed.
Focus - If it has auto-focus and a manual switch for auto-focus/manual focus. The speed of auto-focus can be a deal breaker. You don't notice it until you stand there with the sunset and the girl and the perfect wind - so be aware!
Aperture - Basically how big and small the opening can become. Usually the price for one lens to another can differ 100% from a lens with F 1.4 to a lens with F 2.8. That is a whole step difference but amateurs sometimes don't know and buy the "Best-price" one and think they got a steal. They didn't. Here the rule of thumb is you get what you pay. 
Zoom - If it is a zoom lens - how far it will go and at what quality cost for the whole image. Look at the sharpness in the corners fully zoomed in and fully zoomed out for a quick do-I-like-it that you can do in store.
Gizmo's - Now a days there are quite a few tricks in the Lens-makers-bag. Some important ones can be VR (a stabilizing feature) coating (some coatings remove almost all flare and fringe) exotic stuff like DC (out of focus control) and the sliders and buttons that can make or break a lens.

There are Pros and cons to last a lifetime for a old Greek philosopher - thankfully I'm not one so let's get down to the nitty-gritty:

First: You want as low a F-number as you can get. This have so many advantages it is ridiculous:

  • Low-light photography - you need half the light with a f 1.4 than a f 2.8
  • Bokeh - a big opening renders the fore/background as soft clouds
  • Sharpness - 98% of all lenses perform best when dialed down two or three steps. The lower (bigger hole) you start - the better.
  • Options - you can always get down from a big opening, but you can't go bigger with a small one.


Second: Handling - you must be comfortable with how the lens works. Every pro knows this and we all have lenses with perfect specs that just don't get used. The handling is wrong. It can be as simple as slow auto-focus or that it is to heavy. So the tip here is to try in store or loan/rent the lens over a weekend.

Third: One all-around-lens is a myth. You will always compromise with a 12-300 zoom lens. No matter what the "experts" say. Just look at the lowest F-stop. Oh its 3.5 is it? and that is just at the start of the range, it keeps on down the latter the more you zoom? You probably don't want to go  high-ISO just to zoom in. There are good zoom lenses, look at the F-stop: 2.8 is ok-dokie for a zoom. More than that and I would look for options. One alternative would be if it has stabilization (VR on some makers lenses) then it might be fine at lower.

Fourth: Is it an investment? DSLR's today will be junk tomorrow. Lenses keeps on going for decades - better to buy yesterdays DSLR and put a real lens on it than today's DSLr with a kit-lens.

Fifth: This might be a disappointment so hold tight - The lens don't mean jack. Great photography can be done with a mobile-phone and raw talent (a few pretty people in front might also work wonders) so don't go around thinking you can't afford to take good pictures. Good pictures are all around you. You just need to pull the trigger at the right time, at the right place.