An amateur photographer's perspective.

Disclaimer: I am not a professional photographer. I am doing my PhD in theoretical Computer Science and I enjoy photography. I got my Rebel XT roughly 2 years back and that's the limited experience with which this is written. Hence take my opinions here with some discretion.

Canon EF 70-200mm f/4 L USM

Canon EF 70-300 f/4-5.6 IS USM

Why the comparison?

These lenses are worth comparing because they cost roughly the same (Amazon: Canon 70-200 L, Amazon: Canon 70-300 IS), about 550$ on Amazon at the time of this writing. They are not "cheap" lenses, they are both reasonably good ways to add telephoto capabilities to your arsenal. If you don't have a telephoto lens and you are tight on cash, one of these is a good choice. They differ slightly in what they offer. (If you have lots of money you may want to get the Canon EF 7-200 f/2.8 L IS USM.) Towards the end of this article are urls to reviews about both lenses.

For the past few days I have been playing with Kyle Ross's 70-200 L. I have been comparing this beauty against my 70-300 IS which I have owned for about a year.

The Canon 70-200 is an L class lens. Canon gives the "L" rating to only its very best lenses. It would seem like a no-brainer that one should get the 70-200 lens as opposed to the non-L 70-300. Well, maybe not. What is good for you largely depends on what sort of photographer you are.

These lenses differ on various aspects. The ones I'd like to talk about here are - build quality of the lens, aperture and range, image stabilization and overall image quality.

Build Quality:

The 70-200L is built like a tank in comparison to the 70-300. Its a real pleasure to hold. As a matter of fact, everytime I pick up my 70-300, after I have been shooting with the 70-200, I feel that its about to break. What that means in practical terms is that you need to carry around the 70-300 rather delicately. The 70-200 could last a lot more rough handling than the 70-300 would. Are you the sort of person who will remember to put your backpack down carefully everytime?

In its defense, this is what I have to say: I don't have a special camera bag or pouches for my lenses. I carry my lenses as is in my shoulder bag along with my text books and the camera body. I remember to not throw my shoulder bag around but to place rather carefully on the ground when I am carry lenses.The 70-300 has been fine so far with this sort of of handling, so its not exactly a flimsy lens.

The 70-200 is also much larger and heavier than the 70-300. (I tried to scale the images of the lenses above such that they roughly reflect their relative sizes in real life.) This will make a difference when you start carrying around several lenses. Most photographers end up carry around 3 lenses on the average - a wide, a medium and a zoom.

The last point about build quality I want to mention is that the 70-200 does not extend when you zoom. It is a fixed length lens. The 70-300 on the other hand extends out. So when you back in the lens you have to remember to unzoom all the way. It might be better leave the lens on manual focus when you are carrying to reduce any strain on the externally moving parts of the lens.

If you get a 70-300 you will have to be willing to take care to treat it gently. Also, it does not come with a lens pouch - that will be extra. The 70-200 on the other hand does come with a pouch and a hood.

Aperture and Range:

Having a constant aperture across the full range of the is a big deal. At 300mm the 70-300 can only provide a 5.6. At 200mm it can provide 5.0. The 70-200 can provide an aperture of 4.0 throughout. In practice this makes a nice difference. Going down from 4.0 to 5.0/5.6 make a difference in the DOF/bokeh quality and in the exposure time that you have to endure when shooting indoors in low light.

The 70-300mm on the other hand can provide an extra 100mm of zoom. In practice the difference between zooming from 150mm to 200mm seems to be a much greater difference than zooming from 200mm to 300mm difference. Hence though the extra 100mm may seem to be a big deal, its not that much.

While the loss of aperture and the loss of range are not really comparable, if I had to comment on it I would say that they are roughly comparable. Getting that little extra range is roughly equal to getting that little extra aperture. What is better for you will depend on what sort of shots you tend to take. If you don't have a telephoto, you have no way of knowing this.

I am personally slightly biased in favor of the extra range. When shooting distant things, it does indeed give you that extra bit of detail. There isn't very much softening of the image even at 300mm as well.

Canon 70-300 at 300mm, f/5.6.

The 70-200, being an L class lens, is compatible with some of Canon's lens extenders. These increase the range of the lens with slight reduction in image quality. I have never tried one myself, so I am not sure what exactly the degradation is like. The extender are relatively inexpensive as well (under 300$). This is a way to make up for the lost range. As far as I know, the 70-300 isn't compatible with these extenders.

Image Stabilization:

In short, the IS is fantastic. Zoomed in at 200mm its nearly impossible to handhold most shots unless you are shooting in bright daylight. At 300mm things are even worse. This is where the 70-300IS wins hands down over the 70-200L which has no IS. The only way you can shoot handheld with the 70-200 is under ideal lighting conditions or by jacking up the ISO as high as it will go. Even then the lighting is sometimes not enough for the typical indoor evening scene.

I am disappointed with a large number of my 70-200 shots simply because of camera shake. At those zooms its really hard to hand hold a camera because even the slightest shakes will reflect significantly on the picture. Maybe you have super stable hands, but I doubt anyone can handhold these well enough.

The IS on the other hand enables you to shoot one or two (sometime three) f-stops below what you can without it. This is a huge difference when it comes to taking indoor or evening pictures.

The difference between having IS and no-IS largely depends on what sort of photos you are planning to take. Are you mostly going to be shooting in situations where there is enough light or where you can adjust the lighting? I like taking my camera everywhere - evening walks, friends houses, late night drives etc. Hence, this is not always an option for me. If you are going to be shooting in a studio or some such controlled environment, you don't have to worry about this.

The other alternative is to not shoot handheld at all, but to use a tripod. A good tripod is expensive - a ball head is expensive too. Secondly its heavy and a headache to carry around everywhere and setup. Thirdly, the time taken to setup and compose a shot sometimes makes all the difference between getting the shot or not at all. So, while having the tripod is a solution, its a solution that comes at a significant price in terms of time, money, effort etc.

Even with the IS, there are some shots that I just can get. I don't have a tripod and the trick I use is to set the camera down somewhere and to use a remote to take the picture, thereby avoiding camera shake while clicking. Canon makes a good simple remote for about 24$.

Sometimes despite the IS, both lenses are comparable in low light. Sometime back I was trying to take pictures of some small objects in my living room which has rather low light. I wanted to get a close to the objects as possible to take these shots. As it turns out, the minimum focusing distance for the 70-200 is lesser that that of the 70-300. Hence I could stand closer to the object and take the picture at 200mm at f/4.0 and ISO 1600. With the 70-300, I had to stand further away from the object. Hence I had to zoom in to 300mm to get the same detail, this meant that the f-stop drop to 5.6 and the IS has to struggle with the extra zoom and smaller aperture giving me roughly the same image quality (the 70-300 being sightly better). Cases like this are very much the exception and normally the IS adds great value.

Canon 70-200L at 200mm, f/4.0, ISO 1600, handheld, lowlight, Rebel XT

Canon 70-300 at 300mm, f/4, ISO 1600, handheld, lowlight, Rebel XT

Image Quality:

This is a tricky topic to discuss simply because it has so many facets. We tried to compare the lenses under ideal conditions, shooting outdoors on a slightly cloudy morning. We stopped down both lenses to f/8.0 took some test shots at various zoom settings. If there are any differences in the image quality they were really really hard to tell. In fact just casually looking at the pictures we got, its hard to make out any differences at all.

When zoomed in, there are some differences, especially towards the edges of the images. The 70-200L seemed to do marginally better in this regard. But these differences are so slight that I tend to discard them - in actually photography there are many more things that constitute to making beautiful pictures than such slight differences. If you did a lot of very controlled photography, then maybe these differences matter to you. For my relatively cavalier style of photography, these don't matter at all.

Due to the f/4.0 of the 70-200, some pictures shot at the 200mm end tend to look nicer that the those shot with the 70-300 simply because of the depth of field. I sometimes tend to think that the 70-200's picture have a bit more contrast.

On the other hand, the 70-300 delivers really good image quality even at 300mm - something that the 70-200 simply can't do. Cropping an image to the 300mm equivalent does not preserve enough detail to make them comparable. Also having the IS means that a lot of the pictures come out much sharper with the 70-300. Given a tripod the 70-200 may actually outperform it; but that's a whole other argument.

One last note about image quality is about the usage of polarizers. The 70-300 has a rotating front element. This makes using polarizes rather annoying because they keep spinning around. Polarizers are sensitive orientation and hence after you have focused you have to switch to manual and carefully correct the polarizer before each shot. If using polarisers is important to you, the 70-200 maybe a better choice.

Final thoughts:

Both lenses are fairly well balanced overall. The loss of an f-stop on aperture as opposed to 100mm on range. A better build quality as compared to IS. The take roughly the same quality pictures under ideal settings. What is better for you depends largely on what kind of photography you do. Do you have the luxury of a controlled environment or carrying a tripod? If yes, then the 70-200L is for you. Do you like to wander around and take pictures without much ado? If yes, then the 70-300 is for you.

I own the the 70-300 myself and I absolutely love it. I bought it at a time when I did not have anything to compare against. I wish it were better built and I hope it survives my irreverent handling for many years. Having played with both lenses would I still get the 70-300? Probably yes. However, I feel that in a few years when I developed more taste and style (and own a space-age tripod) my answer may change.

Here are some external reviews of these lenses:

The 70-300 IS:

http://photo.net/equipment/canon/70-300is/
http://www.bobatkins.com/photography/reviews/canon_EF_70-300.html
http://www.bobatkins.com/photography/reviews/ef_70_300is_review.html
http://www.the-digital-picture.com/Reviews/Canon-EF-70-300mm-f-4-5.6-IS-USM-Lens-Review.aspx
http://www.fredmiranda.com/reviews/showproduct.php?product=294&sort=7&cat=27&page=3

The 70-200 L:

http://www.the-digital-picture.com/Reviews/Canon-EF-70-200mm-f-4.0-L-USM-Lens-Review.aspx
http://www.bobatkins.com/photography/reviews/ef702004l.html
http://photo.net/equipment/canon/70-200
http://www.fredmiranda.com/reviews/showproduct.php?product=14&sort=7&cat=27&page=3

Bloomington punishes and Bloomington heals. Seattle stays squishy. :)

My first L-class lens, the Canon 24-105mm L f4.0 IS USM. In short, L-class lenses are Canon's very best lenses. For a while now I have been trying to get lenses for the wide and long end of the spectrum leaving the medium ranges to my now-pretty-much-defunct 50mm prime. I was hoping to stretch and get a real good medium range lens one day. Now it looks like its happening... yay!

This lens is a keeper. I don't think there is something I can think of buying that will replace the utility of this lens. Except maybe if I can ever afford something like the 28-300mm L (which costs 2000+ dollars and would still be clunky to carry around). It was hard deciding between this and the Canon 24-70mm L 2.8 lens, but I eventually decided in favor of the extra range and the IS. My experience with the Canon 70-300 IS USM that I have is that IS is very very handy in low light situations (being a relatively pedestrian photographer, I find myself in low light situations wanting to take pictures rather often, sans a tripod). I can always make up for the aperture by getting a few nice primes, but that can wait.

Looking for the PL group at IU? Go here to subscribe for talk schedules and other updates:

http://mailman.cs.indiana.edu/mailman/listinfo/pl-wonks

Here is a rather pleasant introduction to the philosophical point of view underlying Category Theory.

When is one thing equal to some other thing-

One of the templates of modern mathematics, category theory, offers its own formulation of equivalence as opposed to equality; the spirit of category theory allows us to be content to determine a mathematical object, as one says in the language of that theory, up to canonical isomorphism. The categorical viewpoint is, however, more than merely “content” with the inevitability that any particular mathematical object tends to come to us along with the contingent scaffolding of the specific way in which it is presented to us, but has this inevitability built in to its very vocabulary,and in an elegant way, makes profound use of this. It will allow itself the further flexibility of viewing any mathematical object “as” a representation of the theory in which the object is contained to the proto-theory of modern mathematics, namely,to set theory.

I have been spending some amount of time looking into Category theory and it is truly something elegant. A small selection of topics from Category theory have made their way into my reading list for my Oral Qualifiers. Hence, interested reinforced by need.

One of the strange things about category theory, and probably the most elegant thing about it as well is that category theory really has nothing much to do with objects in the way that Set theory does. Set theory and I think most things deal with objects, collections of objects and such. Category theory on the other hand is a theory about relationships, rather than the objects they relate. This shift, to me, is reminiscent of the Leibniz-Clarke viewpoints on the notion of space.

http://www.ted.com/talks/view/id/145

Armed with a backhoe and a handful of markers, Deborah Gordon studies ant colonies in the Arizona desert. She asks: How do these chitinous creatures get down to business -- and even multitask when they need to -- with no language, memory or visible leadership? Her answers could lead to a better understanding of all complex systems, from the brain to the Web.

Pretty neat talk.

Maybe I should cancel brunch plans

One of the things I enjoy about Windows Vista is the slideshow gadget that comes with the OS. I have pointed the slideshow at my external hdd folders where most of my photos live. Hence this keeps playing back randomly selected thumbnails from my rather large photography set. This brings back rather nice memories at times.

Bloomington is rather cold today (its reached -14 degrees Celsius as of now) and I was thinking about warmer places I have lived in. As chance would have it, the slideshow brought up a picture of the Charminar in Hyderabad. I remember squinting to take this picture in the bright afternoon sun.

The Charminar, Renovations - March, 2005.

From http://en.wikipedia.org/wiki/Charminar

The monument was built by Muhammad Quli Qutb Shah in 1591 to commemorate the eradication of plague, shortly after he had shifted his capital from Golkonda to what now is known as Hyderabad[1]. Legends has it that the emperor Quli Qutb Shah prayed for the end of plague and took the vow to build a masjid on that very place. He ordered the construction of the masjid which became popular as Charminar because of its four characteristic minarets (possibly depicting the first four khalifs of Islam). The top floor of the four-storeyed structure has a masjid which has 45 covered prayer spaces and some open space to accommodate more people in Friday prayers. Madame Blavatsky reports that each of the floors was meant for a separate branch of learning - before the structure was transformed by the imperial British administration into a warehouse for opium and liqueurs.[2]

True to the legend, the city blossomed into a synthesis of two cultures. In 1591 while laying the foundation of Charminar, Quli prayed: Oh God, bestow unto this city peace and prosperity. Let millions of men of all castes, creeds and religions make it their abode. Like fishes in the water.