Killdeer
The New User Corner
Buying a lens
Buying a lens is a serious project, or at least it should be. Camera bodies come and they go after a few years. But a good lens will outlast many bodies. There are plenty of photographers who are still using lenses on their new DSLR that they may have bought back in the 1990′s or even earlier for a film SLR. Thus you should buy the best lens that you can fit into your budget. Waiting until you save money to get a better lens is often better than buying a cheaper low quality lens now.
However there is an active market for used lenses so you can probably sell a less worthy lens for a good fraction of what you originally paid for it. I unwisely bought a Canon 55-200mm lens when I bought my first DSLR ( a Canon 350D and that lens is not the current version with IS). I think I paid a bit over $200 for it and was able to sell it a couple years later for $155 on eBay. So you can correct early lens buying mistakes without a lot of pain.
What do I look at when buying a new lens?
- Focal Length
- Lens optical quality
- Maximum aperture
- Autofocus speed
- Build quality
- Other factors like weight, IS, and noise. And always price.
Focal length
What usually prompts me to start thinking about buying a new lens is when I notice a gap in my lens collection. Or if I feel that one of my current lenses has some blemish on its desirability in my eyes. My last lens purchase was to replace a current lens which I felt had too much flare and ugly hard to edit out flare at that. But I would think that focal length or focal length range in the case of a zoom, would be the most common reason that people decide that they need a new lens.
I have heard from some people who think that they must have a lens that covers every possible millimeter of range from the ultrawide to the long telephoto. I don’t really think that’s true. Right now I have an ultrawide 11-16mm Tokina and the next lens up in my collection is a 50mm prime. I don’t feel any burning desire to cover that gap from 16mm to 50mm. That is what feet are for. You can walk nearer or farther away from a subject and cover the gap without the expense of adding another lens to carry around with you, which will make your camera bag that much heavier too.
Just a note I am going to cover the various lens focal ranges in another post.
Once you have decided on a focal length range it is time to start searching the review sites. Some of the ones I use frequently are:
Fred Miranda’s reviews are all user reviews and as such you have to read them in bulk and not accept any one review as being too important. I always assume that someone who is angry about some product is more likely to get online and write a nasty review than someone who is satisfied is likely to get online and write a favorable review. But that being said, if I see a high number of nasty comments I tend to take them seriously. Fred Miranda seems to have an undeserved bad reputation among Nikon users.
Photodo and Photozone reviews are more technical and are based on actual objective testing. So they will give you an idea of the quality of the lens. Digital Picture is oriented towards the Canon equipment line and has spotty coverage. There are a number of other test sites and using google with the lenses model designation will find more reviews. I also check out the manufacturer’s sites:
I guess a word or two about lens manufacturers is called for here. You first source for lenses is your camera manufacturer. Canon, Nikon, Sony, Pentax, Olympus and others. But third party manufacturers have cracked the camera manufacturer’s codes and produce good lenses. I feel that with the highest grades of lenses from Canon and Nikon those companies are still producing the best lenses. That would be the Canon L grade lenses and the equivalent Nikons. I do not know enough about the other camera manufacturers to comment on their lens quality.
Many of the lens manufacturers provide MTF diagrams on their lenses and look at those can help you judge the lens quality. This is a semi-technical undertaking and the charts were produced by the lens manufacturers so have to be taken with that in mind. The not so technical among us may prefer to skip MTF charts.
Below the top grade lines of lenses the third party companies are in the race with Canon and Nikon producing some very good glass and just like Canon and Nikon producing some junk grade lenses too. You absolutely need to carefully research the lenses you are thinking about buying. No matter who makes them. They all make bad glass and you don’t want to be stuck with one of those.
The third party companies do have a certain reputation. Sigma has been historically fairly safe to buy from but recently they have been getting a lot of complaints about the quality control of their telephotos. One lens rental company has stopped carrying Sigma glass because of the high level of complaints. This situation may have already turned itself around. Tamron has had a reputation of having poor quality control in the past but may be getting better. Tokina has had the reputation of producing ‘built like a tank’ quality lenses but with less than stellar image quality. They still make well built glass but have produced a number of excellent high quality lenses recently. They have the smallest number of models in their inventory however.
Those comments are just based on my subjective observations and may or may not be true at any particular time. You should form your own opinions. And they are not meant to discourage you from buying from third party manufacturers. I own lenses from Canon, Sigma and Tokina and very much like the ones I have. Tamron just never floated to the top when I was done making my evaluations but they do seem to make some nice consumer grade zooms. I just haven’t been interested in those lens ranges.
All of the companies do have a reputation of taking lenses back and recalibrating them or replacing them fairly promptly. But this should make you want to buy from a vendor with the highest reputation so you’ll have someone else to complain to, if you have a problem.
You can also seek advice from Yahoo groups if you are a member of a list there or from local camera clubs if you are lucky enough to have one near you. The least useful source of information is a camera store or big box store. The salesmen get higher bonuses for selling certain products and are thus likely to push those on unwary buyers. You may be lucky and have a camera salesmen, that you know, who is highly ethical.
Magazines also publish reviews but these have to be read carefully. The magazines live by selling advert space and they are not going to enrage a big advertiser by writing an overtly bad review. But if you read the reviews with this in mind they often drop lots of hints. Phrases like the ‘best that can be expected of a lens in this class‘. Faint praise in other words means it is a piece of junk, stay away from it.
Lens optical quality.
Lens quality and cost are somewhat related. You can expect that a better quality lens will cost more since higher quality and more expensive materials are used to make it. Exotic glasses and difficult to grind lens curves are also more likely to be used. Take a look at this video to see what goes into making a $6400 lens. There are several other videos in the set.
The same review sites above will also give you an idea of the lens quality. Lens contrast is also an important part of the optical quality. Some very expensive lenses have the reputation of producing low contrast images. Lenses can also add slight color casts. Some have a reputation of producing ‘warm’ images for example.
Maximum aperture.
The larger (which actually means the smaller the number is) maximum aperture of the lens is also tied to its price. Faster glass costs more and the lens will be heavier. The Canon 70-200mm f/4L lens costs about $600 while the f/2.8L faster version costs $1200. One extra stop doubles the cost of that lens. It also changes the weight from 1.56 pounds to 2.8 pounds.
Better lenses also have a fixed aperture, those lenses above are always f/4 or f/2.8 no matter what their zoom position is. Cheaper lenses will have variable apertures which generally get slower as the lens is zoomed out. Consumer grade telephotos will often start at f/4 at their low end and as you zoom the lens out they will change aperture up to f/5.6. This makes them more difficult to use in low light situations.
Another linked feature is that better lenses usually have non-rotating elements which means that a filter used on the lens will not rotate when you focus the lens. Cheaper lenses will sometime have rotating elements which means that filter will move and you will have to reset it every time you focus. That is important if you use polarizing or special effect filters.
Autofocus speed.
Autofocus speed is how fast a lens focuses. If you are trying to track a flying bird or a running child you want fast autofocus speed. Again better grade lenses often but not always have faster autofocus speed. Some very expensive lenses are notoriously slow to focus and if that is important to you, then check it out carefully. Macro lenses are one class of lenses which often are not quick to focus but most people feel that is less important in that type of lens.
Build Quality.
Like other features this generally tracks price. Some manufacturers have a better reputation, at least in their better grade of lenses. Canon, Nikon and Tokina make sturdy lenses. But it can vary from model to model so check out the one you are interested in. Sometimes you just accept a cheap build quality to get a good optical lens and a low price. The Canon and Nikon 50mm f/1.8 lenses are examples of this. Plastic construction, good optics, and very low prices make these good buys.
Other factors.
There are a lot of other factors that may influence your decision. Is the lens really noisy, some are. Noisy in this case means loud. Does it have IS (if your camera uses lens based IS). I don’t think IS is all that important in shorter lenses but once you get to 200mm and beyond it gets to be very important. The weight of a lens can be an issue. That Canon 70-200 mm f/2.8 IS version weighs 3.5 pounds. Add that to the Canon 5D mk2 body which weighs 2 pounds and you are holding the equivalent of a 5 pound bag of potatoes up to your eye and hanging it from your neck all day.
How the lens focus and zoom rings work can be an issue. Some lenses un-spool and run out to their longest focal length when they hang down. That can be irritating.
And of course price can be very important. No matter how much that Canon 600mm f/4L seems to be exactly what you need, that $6400 price may keep you (and me) from getting one.
Summing up.
So buying a lens can be a long process. But it is one I usually enjoy. It gives me an excuse to search all of those sites. I usually start out with a general idea what I’m looking for, a ultrawide zoom or a long telephoto for example and narrow the list down to 3 or 4 possibilities. Then I use the review sites to focus in on one or two models. I usually ask on a Canon list or two to get thoughts from people I know.
All this takes months for me. I often make a decision but have to start saving up to get what I want. But it is all worth the effort if you get a great lens that you will still be using 10 years from now.