11/15/2012

Zooms vs Primes

One of the main benefits of a DSLR is the ability to change lenses to suit what and where you are photographing.  As you progress beyond the kit lens and start to look at adding to your lens collection, one age old question pondered by many (myself included!) always crops up. Should I buy a zoom lens or prime lenses?  It's a very difficult question because there are a lot of factors to take into consideration including your preferred shooting style, your available budget, and what your main subjects are going to be.  Hopefully what I can do here today is give you some things to think about when you are comparing the two.





First a quick overview of what we mean by prime and zoom lenses - primes are those that have a fixed focal length such as 35mm, 50mm, 85mm, 135mm etc. They do not zoom in or out, so you have to use your feet to get into the right position.  They generally have low aperture numbers (f1.8, f1.2, f2.0) and are fantastic for letting in more light, and creating fabulous bokeh.



Zooms - well, everyone is familiar with what zooms are as they are found on all levels of cameras and are sold as the kit lens with your DSLR.  These allow you to change through the whole focal range of the lens, just by turning the barrel.  Some of these are variable lenses, in which case the focal length is shown by two numbers, for example 24-75mm, or 70-200mm.  These generally have higher aperture numbers that also change whether you are zoomed in or out (F3.6 to 5.6 for example) but you can also get fixed aperture zoom lenses - usually F4.0 or F2.8, which means that you can stay at that aperture all throughout the focal range if you wish. (If all that means very little to you, see the post on understanding the lens numbers)

Now I'm going to list some advantages and disadvantages of each type, but please note that everything I say here is a generalisation of these lenses, and you really need to take into account the quality of lenses to compare like for like - for example if I say primes are generally sharper, I mean compared to a similar zoom of it's class - you can't really fairly compare a top-end zoom with a bottom end prime for example, and expect the bottom-end prime to be sharper.

So without further ado, zooms vs primes....

Why Choose a Prime?

- Primes are much more lightweight than zooms
- Primes are generally sharper than zooms
- The bokeh (blurred background) you can get with a prime is usually much better
- Primes stop down to lower apertures for work with very shallow depths of field
- These lower Apertures also allow you to get more shutter speed (and is why they are called fast lenses) so are great for low light work
- They are usually less expensive than zooms (but bear in mind you will need several to cover the same focal range of a zoom)
- As you will have a range of lenses, you have a back-up if one should need to go away for repair etc
- Some people say that primes allow them to get more creative as they have to move with their feet and think more about the shot

What's the Disadvantages of Primes? 

- They are harder to frame your images with as you have to physically move yourself into position
to get the crop you want
- You will often have to shoot wider and crop resulting in less pixels in your image
- You may have to change lenses for different focal lengths during a "shoot"
- You will probably want to take more than one lens out with you
- You will need several lenses to cover a good focal range

Why Choose A Zoom? 

- Sheer versatility - you only need one lens for multiple focal lengths
- Zooms allows you to frame more shots correctly as you can change your focal length quickly before the "moment" is missed
- Less degradation of picture as you might have to do less cropping (as you can frame quicker)
- You don't need to change lenses so often
- High-end zooms will stop down as low as F2.8 so you can still get great bokeh (although you pay for this particular advantage!)
- You just need to take one lens out with you

What are the Disadvantages of a Zoom? 

- They are generally much heavier than a prime,
- With some very heavy zooms, you can get arm fatigue if using for any length of time
- Although some will stop down to 2.8, many more affordable options have a higher aperture number allowing less light to get into the camera
- Even at 2.8, you can still get more light into the camera with a prime so they are not best suited to low light work
- Most are not as sharp as a prime (with some high-end exceptions)

You will notice I mentioned about that there are some notable exceptions when I mentioned primes are sharper than zooms - one of these is the Canon EF 70-200mm f/2.8L IS II - it is said to be as sharp as any prime, if you add that to the flexibility of the zoom,  and a F2.8 aperture, and you are looking at one pretty amazing lens.........unfortunately with a jaw-dropping price to match!

Generally speaking, zooms are perfect for outdoor sports or other subjects where your subject is moving in and out of different focal ranges - for example, chasing your child along a beach is going to be much easier with a zoom - you don't have to run to try and keep up with them as you would with a prime!   On the downside, the aperture values generally mean these are less suited to taking pictures indoors, and the higher aperture ones are not the best choice for portraits.

Primes are excellent for times when your subject is one place and not moving around so much, and you have a little more time to frame each shot. Classic portrait photography is an obvious example of this.  Also, if you love pictures taken with extremely shallow depths of field, you really can't beat a prime for that.  Lastly, for indoor shots - even for slower sports that are indoors - you might want the extra light that these low apertures affords you.

As you can see by reading this both zooms and primes have times and places where they excel, and one will work better than the other in some situations. Some professionals will exclusively use primes for all their work, and others find zooms to be more advantageous. However, you may find many professionals will have both in their lens arsenal, and of course, this is where the even more old age question of budget comes i! In an ideal world we may want both, but unless you are intending making an income from your hobby, you are probably going to have to compromise somewhere!

I haven't listed any specific lens examples here as you may be getting a little bored of all the lens talk that has been going here lately, but if anyone would like me to create a list of affordable primes and zooms with focal lengths you might want for portraits, sports etc then I'm happy to do so and put in a separate post.......ask and you will receive!


Other Posts You Might Like: 

What Do The Lens Numbers Mean?
Best Lens for Child Photography?
The Dilemma....




6 comments:

Anonymous said...

What lens do you use at your home to capture pictures of your son or say family at a birthday party...where you are all in one room...candid shots? Thanks!

Audrey said...

I use both my 50mm f1.8 (prime) and my Tamron 28-75mm (zoom) -I use the zoom for pictures of more than person as it gives me a little more reach as I can zoom to 28mm and fit more in the frame. I do use the 50mm indoors too, but I can be a little tight if you want to do full body shots so I tend to use this for head shots of one person. Hope this helps!

Anonymous said...

I have what may be a silly question about zooms and primes I hope you can answer anyway. Lets say you have the family in front of the Xmas tree in a smallish lounge room. You want to get them all in the shot but there is a couch a few meters in front of them. Say with a 50mm prime you have to stand behind the couch to get them all in, but that means you get the couch in the picture too! Would the solution be a 30mm lens and you get closer and stand in front of the couch, would that still fit everyone in? With a zoom lens where would you stand? I hope that makes sense! I'm trying to decide if I need a new lens to take photos at Xmas! Thank you!

Audrey said...

Hi, if you are finding that you can't stand far enough back to fit everyone in with your 50mm, you'll need a lens with a shorter focal length - around about 30 should probably do it. Are you using a crop frame camera? If so, this will give you roughly the same view as you see with naked eye, so you should be able to work out if that's ok by standing in front of the couch and roughly gauging it. It doesn't matter really whether you get a zoom or a prime, provided that you have the focal length you need in either, however, a zoom may give you a bit more wiggle room if things are tight. I hope that helped! (if you are still stuck just leave a comment again)

Anonymous said...

Yes that helped thank you! Now I'm just wondering what lens you are going to use on your new camera on Xmas day? You will have a few to choose from!

Audrey said...

I know - I'm so excited! I'm thinking I will probably stick to my 28-75mm as I can squeeze a whole room in with that focal range, plus hopefully get nice enough individual shots. I may stick on my 50mm on the full frame too!!!

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