Replacement of the 18-135 useful ?

Xantra · Feb 17, 2015

Hi,
I currently own a 60D with the kit lens 18-135.
Some month ago I get a 50mm f1.4, and since then each time I come back to the 18-135 I'm thinking "this kit lens is rubbish".

So I stated looking around. I found good reviews on the Tamron 28-75mm f/2.8.
But when I do a quick comparison on DXOMark I found not so much of a difference between my kit lens and the Tamron in terms of sharpness.
Why ? I can find on the web a lot of people saying this lens is really really sharp.

Even when I compare my kit lens to the canon L series 24-70 or 25-105, they are rated the same score about sharpening. Does it mean my kit lens is already good in it's category or we can't trust the sharpening score of DXOMark ? As my 60D is not available in DXOMark I did the comparison with a 50D

Thanks in advance

JacaRanda · Feb 17, 2015

You may be getting caught up by information overload.
Instead of thinking the lens is rubbish, post some pictures here in the forum and let others see and judge what you are thinking.

The 18-135 can be a nice walk around lens on your 60d; as long as you are using it properly for the righ situations.

Use charts as guidelines but let your eyes determine if something is rubbish or not.

Derrel · Feb 17, 2015

Good advice above. One of **the** biggest reasons for "rubbish lenses" is...wait for it, waaaaaait for it...hand-holding the camera at slow to moderate shutter speeds. Many people think that 1/30 to 1/100 second speeds are perfectly fine....well...not always. There's a tendency when shooting hand-held to have a small amount of camera shake, or subject movement, or both. Not on every shot, but often enough that, if you shoot just one or two frames of each subject, and the shutter speeds and lens f/stops being used are similar, an entire session's shooting can end up being shot at the same marginal settings. This issue can be exacerbated during the winter season in many places, where there's a tendency toward exposures that are in the f/5.6 to f/8 range at speeds slower than 1/125 second.

There really can be crisper images attained at speeds in the 1/200 to 1/500 range, by many people. A tripod can eliminate minor hand shake, but if the subjects are not 100% still, there can easily be slight motion blurring. The thing is, with the slower f/3.5~5.6 variable aperture zoom lenses, one is usually working at f/5.6, or slower, like f/6.3 or f/7.1 or whatnot...and those f/stops bring the shutter speed down quite a bit unless the ISO is boosted.

Strict laboratory testing has the camera and its lens mounted on a VERY stable camera stand or tripod, which eliminates loss of performance due to camera movement or hand shake, and also eliminates camera vibration issues as well.

Xantra · Feb 17, 2015

I agree with you, and I'll take some time to select and show you some pictures.
When I'm saying it's not a good lens I was talking about sharpness, even on a tripod with good focusing at f5.6, the picture can be a bit blurry, but not due to bad focussing or camera shake.

goodguy · Feb 17, 2015

Here is an unknown little secret about kit lenses, THEY ARE GREAT!
Well they are great for beginners and in good lighting conditions there is nothing wrong with them, fast zoo lenses really shine in low light situation when you need to bring more light into the sensor and then your slow kit lens show why its so cheap.
If you are shooting mostly in good lighting conditions then dont run to buy fast zoom lens but if you need a more flexible lens well then the 24-70mm 2.8 or some other version of a constant f2.8 zoom lens will be a gift from god for you.

bratkinson · Feb 17, 2015

When I had my EF-S 18-135 pre-USM version lens on my 30D and later 60D, I found it to be more than sufficient for sharpness for my needs. Now, I wasn't doing lines 1mm wide and 1mm apart type 'sharpness' photography, but general photography of everything from landscapes, cityscapes, and some indoor work. Because it went from f3.5-5.6 quite rapidly while zooming, it wasn't 'fast enough' (larger aperture) for no-flash indoor work. I ultimately replaced that lens with an EF 24-105 f4L in preparation for moving to full-frame and I dearly miss the zoom range of the 18-135. I found it to be a great all around lens except in low light. An external flash solved the low-light limitations.

Xantra · Mar 15, 2015

You ask for a pic, there we go. I took this shot some days ago. I'm agree to say the in focus part of the photo is nicely sharp. But in terms of the out of focus blur, I don't find it nice. What do you think ?

Dave442 · Mar 16, 2015

That is about the result I would expect on that shot when focusing on the wind vane. It seems that the issue has changed from sharpness to bokeh.

enerlevel · Mar 21, 2015

out of focus blur will depend on the F stop of the lens... so for example if you shot that pic with tamron 28-75 f2.8, you would get more DOF. or as you call it nice blur..

soufiej · Mar 22, 2015

Xantra said:
You ask for a pic, there we go. I took this shot some days ago. I'm agree to say the in focus part of the photo is nicely sharp. But in terms of the out of focus blur, I don't find it nice. What do you think ?

Any lens is only as good as the person using it. Taking laboratory measurements of a lens is comparable to the old horsepower ratings for an engine not connected to the drive axle or an exhaust system. Or an AV amplifier's wattage measurement with only one channel connected to a load resistor rather than a real world loudspeaker and driven by a single 1kHz sinewave and not a real world music signal. These lab results are not realistic numbers the end user can actually achieve since the manner in which the item is used is not how it was measured.

Does it benefit the user to have better specs going in? Yes and no. With the amplifier, each change in load (the loudspeaker) creates a different load and therefore a different result from the amp for "power", that combination of Voltage and Amperage (combined and over the load value) which goes to making on paper watts. In the end, the loudspeaker's electrical sensitivity is very much more a factor than are the amplifier's "watts". Real world dynamic signals can require an amplifier to produce long term current delivery or short term rise times. Neither of those values are taken into consideration when simply measuring watts. When those two values are measured - as best they can be - the amp is not running at full power or any power typically required by a real world condition. Is the AC power coming into the amp stabilized, scrubbed of noise and constant? Or, somewhat variable at different times of the day and on different circuits coming from the service panel as you would see in a real world listening condition? In short, two amps which measure the same wattage into a constant resistance load resistor in a lab setting can be dramatically different in how they handle a real world load.

A lens stabilized in a lab condition test under ideal lighting conditions, gathering data from a test pattern a fixed distance away from the lens and under otherwise ideal operating conditions isn't the same as a lens on a real world camera taking shots with varying light levels within one single shot, with varying focal lengths and aperture settings in the hands of any shooter, experienced or not. While the test results may indicate the potential for "this" result, the end user might just as well have said, "I like it because it's black."

Are you shooting and processing your files in RAW format? Or, Jpeg? If Jpeg, what in camera enhancements are you applying to the data? Does the lens exhibit greater or similar sharpness at all focal lengths? If so, that would be a rarity for a kit lens. Though from what I've read (and I can't say whether this is truly an accurate statement or not), most in camera Jpeg processing will largely correct for most of the errors created by today's lenses. At what viewing magnification are you making your "this is rubbish" critique? Would you ever actually use an image printed at that enlargement? At what ISO does this lack sharpness show itself? How are your camera's focusing points set up and used? Are you certain the issue is in the data from the camera? Or, could your monitor/printer be at fault at least partially? Are you adding any in camera adjustments which would add some noise and in turn created a less sharp image? Are you using the timer or a remote release for the shutter? Are you judging ultimate sharpness from only a small portion of one piece of a larger image? How does the lens fare when you can fill the frame with one subject to put more pixels on the one image thus sharpening the edges of the image? Are you certain you've absolutely stabilized the tripod to resist all movement? Have you tried shooting in burst or continuous mode to allow the camera to settle down after the initial possible movement of the shutter press?

All of those things and none of those things could alter your results. IMO comparing a single, fixed focal length lens to any zoom lens is rather unfair. Sort of like comparing the handling of a car set up for the track with a stock Camry. The kit zoom offers "this" advantage while the fixed lens offers "that' advantage. Learn to use each for and to its benefits and not as a comparison to the other. There is and always has been since the inclusion of zoom lenses as kit lenses, a very decisive reason for having that 50mm lens as your "best" image maker. Could you have taken your shot above and achieved the same framing with your 50mm lens? If so, then you probably should have if sharpness is one of your highest priorities. That is one of the main reasons for having an interchangeable lens system on a DSLR.

And, in the end, perception is reality. If you feel, after careful consideration and evaluation, the kit zoom isn't sufficient for your needs and has become the stumbling block to your advancement as a photographer, then you should spend the money for a higher grade lens. They certainly exist and in the right hands and under the proper real world conditions will produce superior results. Do so if you feel a $100 bottle of wine is about where you need to spend to be satisfied or that 1000 thread count sheets really are nicer than 400 thread count sheets. If you can spend the money and not put a pinch elsewhere in your budget, buy what satisfies you. If you're taking the money out of your kids' college funds though, ... that is a different story.