I’m a little concerned about the focus performance of my Pentax K10D DSLR. Before I get too far into it, let me  establish a little background first…

Two years ago I was looking for an upgrade to my then 2 year old Canon Digital Rebel XT (350D). I really didn’t have much more than the kit lens and a cheap-o EF 50mm f/1.8 II, so I didn’t feel too married to Canon. I did my research and decided the then new Pentax K10D represented a better value for the $1,800 I had to spend than the more expensive Canon 30D. So, I gave my Rebel to my sister-in-law and ordered up a K10D body, Sigma 18-50mm f/2.8 EX and Sigma 10-20mm EX from B&H Photo.

The ergonomics, features, IQ, and interface were all so much better than my old Rebel that there wasn’t much time for  retrospection. I embraced my new rig and started shooting like mad. Six months and 20K snaps later I had added the excellent DA* 50-135mm f/2.8 to my kit. To my surprise, Santa (in the form of my mom and step dad) gave me a $1,000 Wolf Camera gift certificate for Christmas 2007. Suddenly I found myself in a quandary.

You see, I had become somewhat smitten by the full frame Canon 5D we had at the office for the Marketing team I managed. It had always seemed so out of reach to me and now suddenly it was all-too-close. After a few days of agonizing over what to do, I ended up selling off my K10D kit to a co-worker friend and added the proceeds to my gift certificate. 2008 began with a brand new Canon 5D body (the $3,000 body was all I could afford). Fortunately, my old 50 1.8 was collecting dust in the bottom of a drawer so I was able to actually use the 5D while I saved up for some better glass.

It was hard to draw many comparisons between the 5D and K10D. They really are quite different cameras- with the 5D being much more like a 35mm film camera than a high-tech digital. Plus, the clunky old 50mm prime I started out with on the 5D really wasn’t anything like the Sigma EX zoom lenses I had had on my K10D. What I didn’t know was that I would decide to leave my six figure job in April to return to school and finish my undergraduate degree. This move required scaling back across the board and my beloved 5D (and all the L glass I hoped to own) suddenly seemed like an excessive luxury. I decided to sell it, my EF 50 f/1.8 II, and the EF 28 f/2.8 and EF 85 1.8 USM I had acquired on Craigslist and invest the proceeds into my college fund. For the first time in 7 years I was without a DSLR.

In September of last year my former co-worker felt pity for my situation and gave me back my old K10D with the kit lens off his new K20D! Since then I have been shooting like mad with the kit lens and a 20-year-old SMC-A 50mm f/1.7 manual focus lens I picked up off of eBay. In the past couple of months that former co-worker of mine has also shared his DA* 16-50 f/2.8 and DA 35mm f/2.8 Macro Limited lenses with me to test on my blog. I wasn’t too impressed by the 16-50 (see review) and my experience thus far with the 35mm macro has been mixed (review here).

While I was at PMA a few weeks ago I played around a bit with all the various cameras on display. Both Pentax and Canon had similar demo set-ups for their top-of-the-range telephoto lenses. While using the DA* 300mm f/4 in the bright tradeshow lighting I tried focusing on a subject standing a few meters away and the SDM motor woooshed close then dunk, da-dunk, “beep-beeped” into focus lock. I then swung the lens up and selected a far away subject- woooosh, dunk, dunk, da-dunk, “beep-beep”. Selecting a subject a few feet away from the second the DA* 300 went dunk, dunk, da-dunk, “beep-beep”. This all seemed quite normal to me. From my experience shooting both the DA* 50-135 f/2.8 and DA* 16-50 f/2.8 SDM equipped lenses.

Then, I moseyed over to the Canon booth where they had a very similar display set up with a 1D Mark III and EF 400mm f/2.8 L IS USM lens. Repeating the short-to-long focus test (this time with a much heavier f/2.8 lens) the Canon went woosh, “beep-beep” to the close subject then woosh, “beep-beep” to the far subject. Selecting a nearby subject to the far one I got bump, “beep-beep”. Surprised I tried several more times, panning the camera around and selecting subjects that were just out of focus. Each time I simply got bump, “beep-beep” as the subject popped into near instant focus. At the time I merely chalked this up to the near 10X cost difference between the two set-ups and continued on my way.

Fast forward a few weeks to yesterday and my niece’s 3rd birthday party. I found myself two-fisting my K10D with 35mm f/2.8 Macro Limited and my sister-in-law’s Canon Rebel XT with kit lens (my old camera) while capturing both indoor and outdoor birthday party action. I was immediately aware at how much faster the 4 year old Rebel was locking focus than my K10D was. It was almost exactly like the performance difference I had experienced at PMA.

While the kids were busy taking turns in the kayak (and out of decent photo range for any of my lenses) I took a moment to do a little non-scientific focus testing. I manually set both cameras to infinity focus, selected the center focus point, 35mm focal length (on the Canon) and (in bright sunlight) focused on my hand at around 18″ away, then on the far side of the lake (infinity), then back to a post about 6′ away with the 35mm Macro on the K10D and the 18-55mm kit lens on the Rebel XT. In all cases the Canon nailed the focus point with zero hunting… zip, “beep-beep”, ziiip, “beep-beep”, ziip, “beep-beep”. The Pentax however, struggled a bit. The focus test went weeeee, tick, tick, tick-tick, “beep-beep” for the close subject, then weeeeee, tick, tick-tick, “beep-beep” for the far subject. Then, the camera completely missed the post 6′ away and went weeeeeeeeeeee all the way to it’s closest focus distance than weeeeeeeee, tick, tick, tick-tick, “beep-beep” on the post. (To be fair, this is a macro lens).

Thinking that the Pentax 35mm Macro might have been to blame (which it was), I pulled out my Pentax 18-55 Mark I kit lens and repeated this test again. The results were nearly identical with the exception that the Pentax kit lens did not overshoot the post and merely ticked around a couple of times before locking focus. Also, the lighter less damped focus action on the kit lens did make it seem a tad snappier when focusing between the close subject and the far subject. Incidentally, this time to reach the correct focus distance was basically identical for both the Pentax and the Canon kit lenses. The exception being all the tick, tick, ticking the Pentax lenses did before locking focus. (In case you were wondering I also repeated a similar test inside under poorer lighting with the two kit lenses and got nearly identical results as outside).

Discussing this with my co-worker friend, he relayed the results of a similar test he decided to try with his K20D as follows:

I just did back to back comparisons of the K20d + FA 50/1.4 and my Rebel + EFII 50/1.8. In indirect sunlight, using the center focus point I swapped focus between the front hedge at about 10M away and my left hand outstretched.
The Canon will ziiiiip, stop, confirmation beep.
The Pentax ziiiiips from 10M to my hand quickly just like the Canon but then it quickly zips one (or two!) more times before focus confirmation… Almost like it has momentum from the first movement.
I’ve been fully aware of this (and failure to focus–maddening) but had assumed that after twenty years of screw-driven, TTL autofocus technology this was the best the world could do. Seems it’s the best Pentax can do.
IMHO this is the worst aspect of my K20d.

Keep in mind that his test was done with a state-of-the-art $1,000 K20D + FA 50mm f/1.4 vs a $300 6 year old Canon 300D + 50mm f/1.8 II eBay find.

In hindsight I realize now how many shots I have missed over the years with my Pentax due to its slow autofocus performance. The most frustrating part is that the vast majority of shots I’m missing are while the camera is tick, tick, ticking its way towards focus lock, not because it has mis-focused. Once it gets there it is generally just as accurate as any other camera I have used. I hope Pentax is listening and improves the performance of their next generation of DSLRs. In my opinion, this is much more important than live view, more megapixels, movie recording, higher frame rates, and/or higher ISO performance. Pentax’s DSLRs are some of the best values on the market. Bring the AF speed up to par with the competition would end a lot of arguments in Pentax’s favor.

What do you think?

PS- I excluded Nikon from this comparison because I have very limited experience with their modern DSLRs. However, I did borrow a friend’s D300 + 50mm f/1.8 to take some studio shots of my K10D for my DA* 16-50 f/2.8 review. The camera was set up to use all 50-something focus points in AI mode. Being unfamiliar with Nikon’s focus confirmation implementation I didn’t realize until after I was done shooting that when all those grey boxes popped up in the viewfinder that the camera had locked focus. In hindsight I now realize that it was happening so fast that I was unaware that the camera was focusing. To get my shots BTW, I ended up switching over to manual focus ;-)

UPDATE: First of all I want to make it clear that I am not suggesting that Pentax’s autofocus system is any less accurate than anyone else’s. It is clearly quite effective. Also, I fully understand that Pentax has to pick and choose where they spend their limited development funds and I am happy they put it where they have (weather sealing, in-body shake reduction, user oriented controls, etc). In fact, that is why I chose Pentax over the others in the first place. My main reason for publishing this article was to attempt to draw the same comparisons so many Pentax users have over the past few years in a more objective manner so that those who haven’t experienced the differences themselves could be more fully informed. Too many consumers buy products today based on too narrow a point of view and then blame the product when it doesn’t meet their expectations.

It seems that many Flickrites out there are struggling to get good bokeh shots. The good news is that shooting bokeh is one of the easiest photographic techniques to learn. Unfortunately, it is also one of the hardest to master. Here I will attempt to get you started with the basics. You’ll have to do the mastery part on your own :-)

Bokeh (pronounced: “boke-aay” or “boke-uh”- I prefer the latter) is the out of focus or blurry areas of a photograph. Wikipedia has a much more detailed description of the definition of bokeh that’s worth a read. On Flickr I find most people use the term to specifically describe out of focus highlights in a photo. For the purposes of this how-to we’ll focus (pun intended) on out of focus highlight bokeh.

The photo above made the Front Page of Flickr’s Explore last week. I wish I could say that this was a difficult and challenging shot that called upon all of my skills as a photographer. The truth is this was one of the easiest shots I took that night. These small aperture long exposure shots were a lot more difficult to get right:

The secret to shooting bokeh lies in its definition: out of focus highlights. You need three things to shoot bokeh: pin point highlights, a large aperture and a short focal distance. When I say pin point highlights I mean small light sources. Trying to shoot a large area of light like a window or fluorescent light does not typically produce the type of bokeh “balls” that we are looking for here. Small lights like Christmas twinkle lights are an obvious source, but any light source that is far enough away will become infinitely small and can produce bokeh. I find street and car lights in the distance at night make wonderful bokeh.

Pentax-A 50mm f/1.7 SMC

Next, we need a large aperture. For the novice, the aperture is the opening in the lens that controls the amount of light that makes it through the lens and shutter to the film/sensor. The smaller the f number (or f-stop) the larger the opening. This is usually expressed as f/5.6, f/4, f/2.8, f/1.4, etc. Read more about aperture here.  Typically the larger the aperture the larger the bokeh. Fast lenses below f/2.8 like my 20 year old manual focus Pentax-A 50mm f/1.7 SMC are ideal for shooting bokeh (and is the lens I use for most of my bokeh shots on Fickr).

That is not to say that one can not get great bokeh using lenses with a smaller maximum aperture like the typical kit lenses sold with most entry level DSLRs. The trick is to make sure you are using the largest aperture possible (smallest f number). To do this I recommend switching your camera into Aperture Priority mode (typically labeled “A” or “Av” on the program mode dial) and dialing in the smallest f number possible. With most kit lenses this will be f/3.5. Here is another Explore bokeh photo of mine shot with my kit lens at f/3.5:

The other reason that you want the largest possible aperture your lens is capable of is to ensure that your bokeh is round and not faceted. You see, most lenses use 5-7 straight aperture blades to create the variable opening in the lens. Bokeh takes on the shape and size of the lens opening so smaller apertures will produce smaller, faceted and generally less pleasing bokeh. There are exceptions to this rule as most high end lenses use curved aperture blades that keep the aperture opening round at all f stops. However, if you’re shooting with a $1,500 Canon L series lens I trust you already know how to shoot bokeh ;-)

Aperture openings on a 6 bladed lens (mouse over for setting):

Bokeh shots at different aperture settings with this lens (mouse over for setting):

The last component to getting good bokeh shots is the focus distance used. I have found that the shorter the focus distance to the foreground subject, the better the background bokeh I will get. The idea is to get as much distance between the subject and the bokeh producing highlights. Also, the closer you are focused to the camera the shorter the depth of field (DOF) will be. This ensures those lights way off in the background will be nice and blurred out.

The focal length of the lens is also a consideration. Depth of field is basically a function of focal length, distance to subject and aperture. At a given aperture and distance longer focal lengths result in shorter DOF. A short DOF is what we need to effectively blur the background highlights to produce bokeh. Getting close to the foreground subject and zooming to the longest setting on your lens will likely put you where you need to be to capture killer bokeh.

Here we have an example of close focus on the foreground subject coupled with a wide open aperture and longer focal length to create bokeh from small lights in the background:

When I took this shot I was at the minimum focus distance for my 50mm 1.7 lens (about 18-20″). The white (gold colored here) twinkle lights were on another Christmas tree approximately 8-10′ behind the light bulb and branch I focused on. The other smaller colored bokeh highlights were from other lights on the same tree that I focused on.

TUTORIAL:

Now that I’ve rambled on ad nauseam about all the intricate details of capturing bokeh, let’s get on to the part where you actually go do it!

For DSLR users (point ‘n shooters will have to wait for another tutorial):

1. Set your camera to Aperture Priority mode (A or Av on the program dial).
2. Select the smallest possible aperture (f) number for your lens (should be ≤f/4).
3. Switch your camera to manual focus and manually adjust the focus to the closest setting.
4. Zoom your lens to somewhere around 50mm.
5. Find some nice points of light at a distance of 10′ or greater from the camera (your Christmas tree is the perfect subject this time of year).
6. Fire away!

If you get a shutter speed that’s too slow (ie: less than 1/30 second), try bumping the ISO up to 400 or more. If you do the Christmas tree thing what you should get is something like this:

Depending on how dark the background is (darker usually = better) you might have to dial in some exposure compensation to get your bokeh to really pop. This image looks like it came out fine without any, but I often have to dial in +2/3 to +1 EV for my 50mm 1.7 on my Pentax K10D.

Next, try putting a subject of some sort in front of the camera at the minimum focus distance (or there about) with the bokeh highlights in the background. It’ll take a little playing around with subject matter and lighting (both foreground and background) but in no time you should be shooting bokeh like a pro! For more examples, be sure to check out my bokehliscious set on Flickr.

Please let me know in comments if this is helpful to you and/or if you have any questions or suggestions. Also, feel free to post links of your bokeh attempts for everyone to enjoy. Thanks for stopping by.

Happy bokeh-ing!

UPDATE: This is my single most popular post on my blog. Please let me know what else you would like for me to share about bokeh!