My father is giving me his Canon 50D and Canon EF-S 17-85mm f/4-5.6 IS USM lens.

I noticed that most kits on the market come with the EF-S 18-55mm f/3.5-5.6 lens and I'm considering it instead of the hand-me-down.

I'm looking for the most universal lens, but need help in evaluating the differences between these two and what those differences mean to me as a beginner?

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    \$\begingroup\$ Are you sure your names are correct. The L on the 18-55 seems out of place. The 17-85 is a much more expensive lens so should be of higher quality. \$\endgroup\$
    – lijat
    Jan 29, 2020 at 18:18
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    \$\begingroup\$ This is a follow-on from photo.stackexchange.com/questions/114333/… As you already have the 17-85, I'd go with that. I don't know those specific lenses, but I'd go with 'bird in the hand' vs 'two in the bush'. For a 'first lens' you'll learn more from the larger zoom ratio too. \$\endgroup\$
    – Tetsujin
    Jan 29, 2020 at 20:20
  • \$\begingroup\$ A tip is looking at lens reviews, I will link reviews for these lenses made by the in my oppinion very consistent and balanced reviewer cristopher frost. youtube.com/watch?v=waBjGxsGSg8 youtube.com/watch?v=k40OexNiqGU \$\endgroup\$
    – lijat
    Jan 30, 2020 at 0:16

5 Answers 5


For all practical purposes, any of the EF-S 18-55mm f/3.5-5.6 IS/IS II/IS STM lenses are totally redundant if you already have an EF-S 17-85mm f/4-5.6 IS in good working condition.

What you should not do is buy another lens because it is very marginally better on paper than your current lens. That's how you waste money on GAS (Gear Acquisition Syndrome).

There may be a few edge cases where the extra 1/3 stop of aperture below 32mm and the extra rated one stop of IS may help, but those will be fairly limited to shots that will look barely better with one than the other in very specific scenarios (handheld photos of static scenes in low light). Good technique can go a lot further than 1/3 stop of aperture or even one stop of IS does. If you're using a tripod, as you should for static scenes in low light, or if your subject or other parts of the scene are in motion, then there's no real difference between the two lenses.

Well, unless you want to take a shot at focal lengths between 55-85mm. Which one outperforms the other there should be fairly obvious.

If you really want to replace or supplement the 17-85mm lens with another lens that opens up possibilities the 17-85mm lens doesn't allow, you should think more in terms of true qualitative improvements such as:

  • Faster aperture zooms, like a 17-50/55mm constant aperture f/2.8 lens
  • Wider focal lengths, like a 10-22mm or 10-18mm
  • Longer focal lengths, like a 55-250mm or 70-300mm zoom
  • Very wide aperture prime lenses, like a 50mm f/1.8, 50mm f/1.4, 35mm f/2, 85mm f/1.8, etc. which also tend to be sharper than zoom lenses when stopped down to the common apertures they share with those zoom lenses.

But don't go buying such lenses just because someone else, like me, tells you to. Buy whichever one you need when you realize which one will let you do something you want to do with your camera that your current lens does not allow.

The copy-to-copy variation from one copy of the 17-85mm to another copy of the 17-82mm, and from one copy of an 18-55mm STM to another copy of an 18-55mm STM can be larger than the measured differences between the 17-85mm and 18-55mm STM shown at sites like DxO Mark. So you might wind up with an 18-55mm STM lens that looks better at DxO, but the copy of the 18-55mm you actually get isn't as good as the copy of the 17-85mm lens you already have!

This can be particularly the case when buying lower priced lenses used. Lots of folks will buy/return/sell lower cost lenses until they find a "good" one, which often actually means it matches up to their particular camera body and its variations within manufacturing tolerances better than another copy of the same lens does. But sometimes it means cheaper lenses that are slightly out of alignment show up more often on the used market than more pristine copies. Even with very expensive lenses, finding someone who can do an expert job of lining up a lens is difficult. With cheap lenses, it often would cost more in labor to properly adjust the alignment than the lens is worth, and that's assuming the lens even has provisions for optical adjustments. Some lower cost designs do not. So folks will buy/sell multiple copies until they get one they want to keep.

As we said in our answer to your original question to which this one is a follow-up:

Lens decisions are an intensely personal thing. What one photographer may consider essential can be totally superfluous for another photographer. The more you know about how you want to shoot, the better informed you'll be to decide which lenses are best for you when the time comes to start spending more on gear. What one must be careful to avoid with this strategy is the constant desire to frequently upgrade to a slightly better lens (or camera) than what one is currently using.

and (slightly paraphrased):

At this point you don't even know how much you'll enjoy (or not enjoy) photography as a hobby. Assuming you do decide to stay in it for a while, you might surprise yourself with what kinds of things you find you enjoy shooting the most and what type of things you quickly grow tired of shooting. It would be a shame to find any lenses you wasted money on near the beginning of your photographic journey aren't well suited to what you eventually find you most want to shoot.

In all likelihood, if you decide to stick with photography as a serious hobby, you're going to outgrow either one of these lenses relatively early in your photographic development. Don't waste money buying a redundant lens that is, for all practical purposes, no better and less useful than the one you already have!


In other words, start out at the ground floor and wait there until you know enough to know where in the building you want to end up, then use the elevator to go directly there instead of climbing the stairs one floor at a time using all of your energy (money) wandering around looking for where you want to go.

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    \$\begingroup\$ This is a great answer. I'd like to just add- don't diss 'hand me downs'. If you're a beginner you simply do not have the experience to know what you need or not. In fact one of the lessons I learned early from a National Geographic photographer was this: You don't pick lenses, your subject does. Sounds crazy- but if you have a scene you want to 'stack up' (compress) you pick a telephoto. Otherwise you get closer. If you have a scene you want to soft focus, you pick a fast lens. The bonus of more light is that- a bonus. Too many details for just a comment though. \$\endgroup\$
    – J.Hirsch
    Jan 30, 2020 at 15:52
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    \$\begingroup\$ I'd put more emphasis on the prime lenses. Of course the value depends a lot on the use cases: If you are always outdoors at daylight you'll be fine with small apertures, and consequently the quality differences between lenses are less relevant. But if you want to take the one memorable shot of a grandpa and grandchild at candlelight you'll want a prime lens. Of course a 50mm/f1.8 is the best value for money and is also easy enough to carry. \$\endgroup\$ Jan 31, 2020 at 16:38
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    \$\begingroup\$ One of the best exercises is finding out what you can and cannot do with your current lens. Until then, you don't know what you need to do what you currently cannot do. \$\endgroup\$ Feb 1, 2020 at 2:27
  • \$\begingroup\$ @Peter-ReinstateMonica The entire point of this answer is to let the OP discover what lenses they need for what they want to do, not for what you or I want them to do. You're free to put whatever you wish in an answer you write. \$\endgroup\$
    – Michael C
    Feb 1, 2020 at 12:23

The EF-S 18-55mm has had many iterations over the years...so when you say you're considering the 18-55mm, you need to be specific to the EF-S 18-55mm f/3.5-5.6, EF-S 18-55mm f/3.5-5.6 II, EF-S 18-55mm f/3.5-5.6 IS, EF-S 18-55mm f/3.5-5.6 IS II, or EF-S 18-55mm f/3.5-5.6 IS STM?

I'm assuming that you're shopping new lenses, so you'd run into either the IS II or IS STM. For the comparison below, I'm assuming you're looking at the IS STM version.

The differences are:

Focal Length

  • 17-85mm vs 18-55mm...The difference at the wide end is negligible - but you will notice the difference at the telephoto end. ~80mm is a great headshot portrait length and allows you to zoom in on farther away objects.
  • Winner: 17-85mm


The widest open aperture dictates the most amount of light that you can get through the lens. There is an inverse relationship between the number and size of the aperture; f/1.2 is much larger than f/4 (How f/stops are measured is it's own question that I hope you explore). For now, know that a larger aperture lets in more light but also shrinks the Depth of Field, which is the range of optimal sharpness around the focal point (again, a large subject).

  • 17-85mm f/4-5.6 vs 18-55mm f/3.5-5.6...the 18-55mm STM has 1/3 of a stop more light coming in at focal lengths below 32mm as compared to the 17-85mm. At focal lengths above 32mm, they're very close. At 55mm the 17-85mm is actually slightly faster than the 18-55mm. What's 1/3 stop? Let's say that you are taking a picture and the proper exposure is 1/60 second at f/4. Opening up to f/3.5 would move your shutter speed to 1/80 second. 1/3 of a stop isn't all that much, but there are some cases where it could make a difference, so...

  • Winner: 18-55mm below 32mm, 17-85mm at 55mm

Image Stabilization

Not much to say here, they both have it. But, the 18-55 STM is a much newer lens and does benefit from some newer tech here...

  • 17-85mm has 3 stops correction vs the 18-55mm's 4 stops correction...The 18-55mm has an extra stop of correction, which is the difference between 1/15 shutter speed and 1/30...which might just do it in low light handheld scenarios. But, keep in mind that the 18-55 is 1/3 stop faster as well...so the benefit of the IS plus the 1/3 stop faster leads to an overall benefit of 1.33 stops. Also keep in mind that IS does nothing for moving subjects, it only helps with reducing the impact of camera movement when shooting static scenes.
  • Winner: 18-55mm


  • 17-85mm USM vs 18-55mm STM...USM is faster, but STM is smoother. Videographers favor STM since it is less jerky while still shooters photographing things that move fast prefer USM. One isn't really better than the other in general...but depending on your needs, you'll choose a side.
  • Winner: Tie

Sharpness and Pixel Peep Tests

Pixel Peep tests are really not worth a whole lot to me - there are lab scenarios and then there is real life shooting. But, I'll put DxO Labs' measurements here

  • TL;DR...both lenses are great entry level lenses, and both are also not the sharpest thing out there. Their scores are very close together with an ever so slight edge going to the 18-55...but it is a very slight edge.
  • Winner: Tie


In the 18-55mm focal range, the 18-55mm slightly outperforms the 17-85mm in terms of sharpness, light transmission, etc.

But here's the deal: if you need to shoot at 85mm, only one of these two lenses will get you there.

I can't make the decision for you, but if it were me, I'd keep the 17-85mm. FWIW my first lens was a Sigma 24-105mm f/2.8-4 lens.

You need to start shooting and learn a thing or two before you develop your lens wishlist. There are countless pages on forums of this is better than that and bla bla bla.

Shoot with the 17-85mm for awhile. Pay attention to what you like to shoot and what focal lengths you shoot the most. Make note of when your lens isn't doing what you want...maybe you're shooting sports and are at the 85mm end a lot and really wishing it could go longer. Or maybe you're right in the middle of the range and shooting at f/4 a lot and wishing you could get to f/2.8.

What you shoot and how you shoot will dictate your lens needs. You won't know this until you go shoot!

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    \$\begingroup\$ Agree with the part about knowing your lens well before deciding what you want to do that the one you have cannot. \$\endgroup\$ Jan 29, 2020 at 23:16
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    \$\begingroup\$ The 18-55mm is 1/3 stop faster than the 17-85 only below 32mm. At 32mm and up they are measured virtually the same (the 17-85 actually transitions from f/4.5 to f/5 one mm longer at 38mm than the 18-55mm STM at 37mm). Bu the fact that the 17-85mm holds f/5.6 all the way to 85mm indicates that it is probably slightly faster (but still closer to f/5.6 than f/5) than the 18-55mm at 55mm. The 'Transmission' tab at your DxO link bears that out. \$\endgroup\$
    – Michael C
    Jan 30, 2020 at 0:03
  • \$\begingroup\$ "How f/stops are measured is it's own question that I hope you explore" by reading the several existing Q&As here, not asking a new one! \$\endgroup\$
    – FreeMan
    Jan 30, 2020 at 13:51
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    \$\begingroup\$ The 17-85mm has the advantage on price, as it is free. The money that would have been spent on another lens could be put to a lens blower, a camera bag, memory cards, and a card reader, say. So the difference to a new user would be the accessories. \$\endgroup\$ Jan 31, 2020 at 20:50

The 17-85 has image stabilization which all in all allows you to take better photos. That combined with a larger zoom range makes it more universal.

  • \$\begingroup\$ But, note it's also f/4 at the wide end, as opposed to f/3.5, so there's slightly less light-gathering at that end. \$\endgroup\$
    – twalberg
    Jan 29, 2020 at 21:00
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    \$\begingroup\$ @twalberg IS more than makes up for that. \$\endgroup\$ Jan 29, 2020 at 21:21
  • \$\begingroup\$ With respect to hand-holding, yes. But on a stable tripod, in low lighting, where IS isn't going to help at all, that extra half stop might on occasion make a difference... \$\endgroup\$
    – twalberg
    Jan 29, 2020 at 21:39
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    \$\begingroup\$ I have both, once I bought the 17-85mm, I hardly ever used the 18-55mm. \$\endgroup\$
    – Mattman944
    Jan 29, 2020 at 22:48
  • \$\begingroup\$ @twalberg Which is what beginners do most, right? \$\endgroup\$ Jan 29, 2020 at 23:15

Not much to say after Hueco's answer.

You do not get a new lens just because.

Find out what you need and what your current lens lacks and based on that you get a new lens. But in general terms, you do not buy a lens that has similar characteristics to the one you have.

You could go for a prime 85mm lens for portraits, or a zoom telephoto, or an ultra-wide lens, etc. Not one that similar to the one you have.

Go and ask your father why he purchased that lens, and enjoy it.


Why not take both and find out?

The whole point of interchangeable lens cameras is having multiple lenses, and starting with both will give you a lot of learning experience early on about how lenses differ. Also, you might want to add some prime lenses and a 70-210 as soon as you have some money to spare ...

Many readers here will have more than 5 lenses, certainly a few handful will have more than 50.

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    \$\begingroup\$ The point of interchangeable lens cameras isn't to have multiple lenses, it's to be able to shoot to a wide variety of requirements. Having multiple lenses is the way that goal is achieved, not the goal itself. In this case, the conditions the 18-55 (which OP is thinking of buying) is good for is practically just a subset of the conditions the 17-85 (which they already have) suits. There's no point in OP buying a second lens unless it actually allows them to do something the other isn't (at least almost) as good for. \$\endgroup\$
    – Chris H
    Jan 30, 2020 at 7:44
  • \$\begingroup\$ Killjoy :) ..... \$\endgroup\$ Jan 30, 2020 at 8:58

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