Jenobandito

I plan on purchasing the Canon 70D. I am getting confused on lenses to get. There are the kits with included 18-135mm lenses, but since there are different grades, I am puzzled. After looking at many review sites, I am still confused. Price is a factor. So an option is to buy used or refurbished, but still, which lens. I presently have a Canon 28-135mm and a Canon 20mm. Photographs with either lens have recently shown lack of sharpness, so I think my problem is the Canon 40D, and am currently figuring out what to send in to get fixed.

B&H has a used Tamron AF18-270mm f.3.5-6.3 Di11VC for sale that I would like to know what people think of the sharpness of that lens.

If my 28-135 is OK, that lens will go with me to Africa in October. As will my Canon 100-400, which is old and not the sharpest, but acceptable for me.
I will not go to Africa again, so plan on taking both bodies, and the zooms.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

A very short tutorial:

Any EF lens will work on any Canon EOS DSLR. L lenses are premium quality and designed for full frame EOS cameras but will work very well on APS-C cameras such as the 70D or 80D or the Rebels. They are positioned as premium and typically carry a premium price. EF lenses (apart from a few - the EF 75 -300mm variants ) are a good choice for longer lenses.

EF-S lenses are specifically designed for APS-C EOS cameras (such as the 70D or 80D or the Rebels) and some are excellent, almost L quality optically, but will not function or mount (easily or safely) on full frame EOS cameras.

For the 18-135, which are all EF-S lenses - so APS-C only - there are three generational variants. The oldest - the 18-135 IS - is not a bad lens optically but uses the oldest type of Canon autofocus motor - the micromotor - so is best avoided.

The next two generations 18-135 STM or 18-135 USM are both very good optically and work well with both video and still photography. The USM version costs slightly more but has the latest Canon autofocus motor - nano USM - which works well for both video and still photography. That would be my choice, although I have the STM (before the USM came out) and am not disappointed.

Hope that helps in a small way.

Good luck

Kuzano

Part of the dilemma is your expectation is that digital produces sharp images, and that somehow this can be overcome with higher priced or "high grade" lenses.

Your expectation is only partially correct, but the first part of the sharpness equation is the fact that the generation of camera you are using uses AA filtering, which purposely smudges sharpness in digital image generation. You are not aware that you are starting with a flawed concept of sharpness and therefore not prepared to learn to "sharpen" images in post processing.

Now most of the digital camera manufacturer's have deleted the low pass or AA filter from their initial filter in front of the sensor, or before the image is written, applying the "smudge" to sharpness. Your 40D is not among AA filterless practice, so is not a good guage of a sharp lens. In fact Canon is one of the holdouts on relieving the low pass filter problem, and may also NOT have removed AA (low pass) filters.

So, while lens sharpness is a factor of better (more expensive) lenses, your concern before spending money should be with a full understanding of the AA vs. no AA filter, and the proper functions for sharpening in post processing to eliminate what the AA filter adds to the problem, prior to concern about
"what lens is best". Huge amounts of money have been spent on lenses before determining and correcting a mfr designed and built in sharpness problem IN THE CAMERA BODY.

There are, and have been for some time, companies that have provided solutions removing or correcting the AA (low ass) filter smudge. This is not a cheap process, and mfrs have simply modified their camera's by removing such filtering. Nikon.... no AA filters on many models. Fuji... never done such filters. Olympus, dropped aa out in 2006-2007. And others as well.

Are you doing any sharpening in Post to resolve your problem. Do you know if the Canon you are considering has AA filters? I have not seen any references to Canon following suit on that score.

AA Low Pass filtering is a complex situation, and you would be well advised to spend your time to understand how it can be a big part of your lens decision and cost.

Or, you can simply spend untold dollars buying lenses that will never satisfy your criteria for sharpness, without looking at other parts of the equation.

Why do you think there are so many of the high level Canon and other upper grade lenses for sale used on eBay?

Oh Yes, and an aside here that you did NOT want to hear, and not sarcastic at all.

If you want the full sharpness your lenses are capable of producing, shoot film. I'm serious. Buy a good late model Canon EOS film camera and test your lenses on film????

You may be pleasantly surprised to learn no shortcomings on your lower level Canon lenses AT ALL!!!

Jenobandito

Oh my. No. You are correct, I know nothing about that. I just did a short research session before coming back and responding. It is still confusing to me, but I still am learning. Also, I use a MacBook Pro, and I just experimented with the sharpening tool. I did notice a small difference, but the images that were soft were shot with the 109mm at 125 f20 and there is no reason it should be soft......Is there a program you would recommend to use on editing (price is a factor) and better than the built-in on the Mac?

Jenobandito

Thank you, I replied the the wrong spot. Actually, the 20mm lens cost $700 when I purchased (probably 20 years ago, therefore not the latest technology) and was not a low level lens , however it did not seem sharp in the test. Possibly I am just becoming more critical and haven't noticed this before. Yes, using my EOS 10S would be a good test with these lenses. Thanks for that advice.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

125 is a little slow for 109mm on an APS Camera (potentional camera shake / motion blur) - 1/200 or faster would be better, f/20 is a little too small and could cause diffraction which results in softening of the image.

There are many good - even free - image manipulation packages.

There are some technique issues relating to shutter speed and aperture value that you may benefit from exploring. It may not be the equipment.

Kuzano

If you are responding to my AA (low pass) filter narrative (please use "show quote" button) then the simplest solution is not to waste time using software approaches to "sharpening" to overcome the first impediment to sharpness, but to abandon those camera's that do still use AA Low Pass filters in front of the sensor, or spend the $500 thereabouts to have the filtering neutralized by the third party companies that do such things.

I consider it a poor choice to continue to try to use a software solution to sharpen EVERY image shot by a poorly chosen camera. If the camera is capable of a sharper image written to the memory card in the first place, that would be the best solution.

I consider it also some what of a "screw" job on the part of an industry that has compromised the hardware we buy (lenses particularly) by the use of the Low Pass filtering method, ie smudging sharpness at the point of writing to the memory card.

I am heartened by the manufacturers that have removed such practices, and righteously pissed off by those who ignore this issue. (Canon?)

I shoot Olympus and Fujifilm. Olympus since about 2006 when they weakened and then removed AA filtering, and Fujifilm, who has never used AA filtering on any of their sensors. Nikon has dropped such filtering most of their latest models... (not all). Canon is on my DNB (Do Not Buy) list if that means anything to others.

To me, the biggest hurdle if looking for sharpening in post, would be to first attempt to nullify the impact of the AA filtering and then move forward from there. I have no idea how one would go about that, other than to avoid the AA filtering in the first place. ie. remove it from the camera body!!!

Jenobandito

Thanks.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

Your attitude is showing!

Jenobandito

Thanks. I learned in photography class 30+ years ago that shutter speed corresponded to focal length, therefore 125th for focal length of 109mm. I guess I still have a lot to learn. I will continue to experiment with my equipment and see what comes from it. Thanks again.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

That formula is based on 35mm or "full-frame" angle of view. The use of smaller sensors changes that - 1.6 "crop factor". This doesn't change the focal length of a lens but can magnify camera shake so from an operational point of view you could consider 109 mm as being subject to the shake effect of a 175 mm lens, essentially hitting a smaller target, so 1/250 or faster is a good choice. Also, f/8 or close could be the sweet spot for the lens. I would experiment and see what you find.

Jenobandito

That explains a lot. I did a quick test and the photos seem sharper.....even if it is a Canon

135mm @ 1/160 f8

(Download)

28mm @ 1/40 f18

(Download)

20mm @ 1/40 f14

(Download)

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

I would still go for faster shutter speeds and larger apertures and try again. Nice subject.

Been a Canon user since 1976, some lenses are sharper than others. In the digital age some sensors are better than others, Canon, although still catching up is doing better and better and they make their own tech.

Canon is also stronger financially than either Nikon or Sony's camera division that makes the sensors for other camera vendors such Nikon and Pentax.

We live in an interesting world. Expect it to keep changing.

Jenobandito

It is like I am starting all over again. If sharpness leans toward larger apertures (taught that smaller was sharper) then the depth of field becomes an issue. Trial and error. I am excited to keep experimenting!

I still plan on getting a 70D, and your suggestions on lenses helped, too. Since it is almost less expensive to get a bundle than a stand alone camera, chosing the best lens for my uses make sense.

Canon has been my camera and lens choice for many years, (you would think I would have a better handle on it). I have an EOS 3; EOS 10D; EOS 10S; and a Rebel 2000. There are also a multitude of lenses in my collection.

Thank you. You have been very helpful.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

I still have an AE-1 and a T90. The aperture size thing changes with digital sensors from what I am led to believe. Film and digital technology are not a simple one for one replacement.

Do a google search on lens diffraction. It may yield some useful results. Here's one to start with: http://www.bhphotovideo.com/explora/photography/tips-and-solutions/lens-diffraction-what-it-and-how-avoid-it

I also use some old Canon FL/FD lenses adapted to modern EOS digital cameras. That's a whole other ball of wax, but can be interesting!

Take care.