Pentax K20D, A Jeep and a Pentaxian.

Last Monday, I got up early and drove to Silverwood Lake in Southern California. It's about twenty miles from where I live. Once there, I decided to drive up a dirt road that took me all the way to the top of the San Bernardino Mountains. What a nice quiet day this was. I was alone, and I stopped often along the way up to take some pictures. I had my K20D, the DA 16-45, the DA 10-17 and the DA 50-200. The higher I got, the fresher the air got. Only the sound of birds and wind could be heard. It was just me, my camera, my Jeep and Mother Nature. All the stress of the daily grind was gone.

There is nothing like taking a day off and go somewhere away from you job, your family, your town, and everything that you have to deal with on a daily basis. Instead of shooting like I had no time to spare, I took my time and composed the shots carefully. Instead of taking 1000 pictures like so many of us do, I shot less than 100 pictures through the whole day. We live in a ridiculously fast world. We're in a hurry but we don't know why.

Even my pictures taken that day transcend a feeling of peace and tranquility. Of course, it was peaceful and tranquil. I posted some of the shots that were good for pano here and I hope you like them. I might post pictures of the flora at the 8000 ft altiture. It was spectacular.

I had time to use my tripod, check the composition many times before taking the actual pictures, and was not pressed to hurry up at all. I came back home rested and with more keepers than duds. I turned some of the pictures into fake panoramic pictures by cropping the large 14.6mp images that the K20D produces.

All and all, it's good to get away from it all once in a while. You ought to try it. When the stress is gone, your creativity kicks in...I think!

Thank you for reading.

Yvon Bourque

K20D AF Adjustment Chart expanded as per the constructive comments received.

Hello Pentaxians and friends,

Yesterday I introduced an AF Adjustment Chart to help in determining if any particular lens has front or back focus problems. As I often do, I posted the major portion of the article on various Pentax forums. Several Pentaxians emailed me with some good suggestions as to how to improve the chart. I first tested the chart with a lens that focused as close as just a few inches and my chart actually worked at eliminating the back focus problem I had. The lens was a Pentax SMC-F 35-70mm macro. Every time I would take a macro picture, it seemed that the actual photograph would be out of focus when, I was certain that I had focused properly. The K20D, with the AF Adjustment function was the right camera to test and adjust the lens.

I recognized yesterday that the target cross was too small for constant and accurate results. I changed the chart and incorporated a much larger center portion while retaining the overall design. Additionally, I scaled the center portion to almost the size of an 81/2” x 11” letter size paper. I still believe that it is easier to have the chart standing at 45 degree from horizontal while testing the lenses with the camera on a tripod and as horizontally leveled as possible.

If you look at the chart, the center is oval in shape when viewed perpendicularly. The reason for this is because when focusing on the chart with your camera leveled, you will notice that the oval shape turns into a circle, helping in visualizing when the camera/lens is leveled.

The oversized chart can be attached to the smaller chart with paper clips, to retain the 45 degree angle. It is at 45 deg because that way, the depth of field can be seen. If the sheet was flat, there wouldn’t be any depth to it. The Metric and English dimensions are accurate on the small chart, but the enlarged chart shown the dimensions also enlarged. Still, it does show if you have back or front focus errors.

Again, if other suggestions are emailed to me, I will first make sure that we all agree with the improvements and re-issue a once again improved chart.

Now, I assume that we all own and use Pentax equipment. My blog, the other Pentax blogs, as well as the dedicated Pentax forums should all have one thing in common. That is to help each other as Pentax users.

The reason I am bringing this up is that I experienced some rather condescending comments from some members of forums. Its one thing to share your knowledge with the entire Pentax audience, but it’s another thing to be rude and pompous toward other Pentax brothers and sisters. I won’t name any of the forums, as I am sure you already visit every Pentax sites on the internet. At the top of the list for rudeness, is a member from Hong Kong whose name you probably already know. That person should tone down a little from his self-proclaimed expertise.

A Pentax site should be embracing all Pentax users from the person with no experience that just bought a Pentax DSLR today to the most talented and experienced professional photographer in the world, whoever that is.

I wrote before that owning a Pentax DLSR was like being part of a big family. I truly believe that Pentaxians are a special loyal group. Let’s help each other become better photographers by helping each other.

Thank you for reading, and thank you for all the constructive comments.

Download the AF ADJUSTMENT CHART HERE.

Yvon Bourque

Above is the new chart with a much bigger and uncluttered center. It is cut and folded in the same way as the previous chart.

The picture above shows the new chart standing at 45 degree from horizontal.


Above is the chart from behind.

Above is what I saw in the viewfinder with the DA 16-45mm at full aperture and as the closest point it could auto-focus.

Above is the enlarged chart, clipped to the smaller chart retaining the 45 degree angle. It is included in the free download.

Above, you can see the enlarge chart clipped to the smaller chart from behind.


Above, you can see the oval shave when viewed perpendicularly to the chart.

Above is the test of the Pentax DA 70mm Limited. It's a very sharp and accurate lens. Notice how the oval is now an almost perfect circle?

Finally, the picture above was taken today, atop the San Bernardino mountains, to show that I am not a pixel peeper, I do take real photographs.

AF adjustment test chart to help with the Pentax K20D Custom Setting No.34

Hi Pentaxian and friends,

The Pentax k20d has a special function located in the Custom Setting menu. It is Custom Setting No. 34 and it is called Focus Adjustment. According to Pentax, all newer DA Series of lenses are tuned at the factory for proper focus with all Pentax DSLR bodies. However, the older K-mount lenses may produce back or front focused images. The K20D’s AF Adjustment function allows the adjustment of the focus position for these lenses and can store up to twenty lenses in its memory. It is also possible that newer DA lenses need adjustment as well. Any high precision instruments, such as modern lenses, may need calibration once in a while. With the K20D built-in firmware, you can check and adjust all your current Pentax K-mount lenses.

Reading the Pentax manual, or our book, the Pentax K20D “Everything you need to know…and then some” for that matter, the AF Focus adjustment function is explained, but there are no adjustment chart to comprehensibly adjust the focus of any lenses. A bench mark chart is required. There are a few AF focus check charts floating around on the internet, but I have not seen any designed specifically for the Pentax line of DSLRs and lenses. The charts I have seen on the internet were all designed with the Nikon products in mind, although there are no in-camera adjustments possible with these DSLRs. All you do is checking the back or front focus problems so that you can send your lens or lenses to the manufacturer for adjustment. On all the charts I have seen, either the English measurement scale or the Metric measurement scale were incorrect. I also noticed that they required laying the chart on a flat surface and position the camera at 45 degrees, which is a little difficult to do accurately.

Well, it took me a little while, but I designed a chart for the Pentax line of DSLRs and lenses. It is free for the download amd will also be included with all K20D books. It is very simple to use and will stand at exactly 45 degree on a flat surface, requiting you to simply set your camera horizontally. The chart was designed with AutoCAD. (This is an engineering design software package, for those of you that are not familiar with AutoCAD). The chart measurements are exact and adjusted on the 45 degree plane to reflect and measure the exact back or front focus depth. In other words, it shows the exact depth of focus measurements in millimeters or inches, from the 45 degree position. It just required a little trigonometry formula for right angle triangle.

The actual method of checking your lenses is written on the sides of the chart. You can download the chart here, Pentax K20D AF Adjustment Chart Revision 1.

Here are the instructions for setting it up. You can use the chart as you please and distribute it to anyone, but you cannot sell the chart or reproduce it for publication without written permission. I think that’s fair enough.

1. After downloading the PDF chart, print it preferably on a thick stock letter sized paper. I used a matte photo paper with a 61lb weight / or 10 mil thickness.

2. Next, cut the chart where is says “Cut at line”. 3. Score the chart where is says “Score and fold”. Scoring simply means to use a straight edge and a dull side of a knife and tracing along the line to make an indentation in the paper so that folding becomes easier and precise. 4. Fold the chart as shown. 5. Staple of tape the chart pointed end as shown. The angle is already adjusted so that the chart will lay exactly at 45 degree when placed on a flat surface such as a table or desk.
Use the instructions on the chart to test your lenses.

If your lens AF is adjusted properly, it will look like the picture above. The target cross is in perfect focus.

If your lens AF has front focus problems , it will look like the picture above. The target cross is not in perfect focus. The point of perfect focus is in the front of the target cross. You need to adjust the front focus by half the distance of focused area. In this case it looks like 4mm will do it.

If your lens AF has back focus problems , it will look like the picture above. The target cross is not in perfect focus. The point of perfect focus is in the back of the target cross. You need to adjust the back focus by half the distance of focused area. In this case it looks like 2mm will do it.

You can read the chart directly on the camera monitor with the zoom function, but I found it was easier to print it.

That’s all there is to it. I hope you find the chart useful and please email me with your questions or suggestions. Don't take yourself too seriously, and just adjust your lens if you consistently have many pictures with front or back focus problems. You might be the problem, not the lens.

Best of all, go out and take pictures. The world is not made of pixels. Go smell the flowers and take pictures of them.

Thank you for reading,

Yvon Bourque