Kid shots with FA77/1.8

The image quality of FA77 is very good, giving very pleasure result. However, the focus speed on my istD is quite slow, and cannot lock into correct focus quite often. It's a big problem with kid's shot, so I have to resolve to use MF. Although the f/1.8 make it very easy to MF, I still hope the AF speed problem can be solved in other DSLR models.

A few bird shots with Tamron 70-300/4-5.6 LD

The depth-of-field myth on APS-DSLR

A common question: "how does the depth-of-field on 1.5X crop factor (APS size) compare to full-frame film?"

I don't want to go into the theoretical and mathematical details of depth-of-field. So I will use a Palm program to solve this. The circle-of-confusion used by the program is 30um for full-frame, and 25um for APS-DSLR.

In short, the DOF is affected by: focal length, shooting distance, aperture, and film (sensor) format. So the above question is a tricky question because it has 2 different answer. The DOF on 1.5X DSLR is bigger then 135 full-frame, and it's also smaller. It all depends on how you look at the question.

First, if you are using 'equivalent' lens on your DSLR, shooting at the same position, using the same aperture.... the DOF on DSLR is greater than full-frame film. eg:
full-frame: 75mm lens, f/2, distance=2m
APS-DSLR: 50mm lens, f/2, distance=2m
You will get the same framing and perspective with the above 2 setting. But the DOF with APS-DSLR will be bigger than full-frame 135:
DOF of full-frame: 1.96m to 2.04m, ie. 8cm
DOF of APS-DSLR: 1.92m to 2.08m, ie. 16cm

So, many people say full-frame has more 3D feeling than APS-DSLR. The main reason it the difference in DOF: a shallower DOF gives more 3D feeling.

On the other hand, if you are using SAME LENS, shooting at SAME DISTANCE, than the DOF of APS-DSLR will be shallower than full-frame 135, eg:
full-frame: 50mm, f/2, distance=2m, DOF=1.91m to 2.10m, 19cm
APS-DSLR: 50mm, f/2, distance=2m, DOF=1.92m to 2.08m, 16cm
So if you are going to use the DOF scale on your lens, the DOF on APS-DSLR will be approx. 1/4 stop shallower.

Submit your shutter count

HERE.

Someone has tripped the shutter of istD for over 130,000 times, and still living. Not bad.

Tokina ATX 828 (80-200/2.8)

The old story: there is no large aperture tele-zoom from Pentax, period.

The FA*80-200/2.8 is not only expensive, but not readily available on the market. So I get the Tokina ATX 80-200/2.8 a few years ago, to fulfill my long wish to own an heavy tele-zoom.

Just a few days after I get my ATX 828, I regarded. The lens is very heavy, and I don't really have that strength to bring it out. After owning this lens a few years, I can only a few samples taken with it in my hard-drive.









To be honest, the lens is not bad. But it's not that impressive too.

On the picture quality side, the image is quite soft at f/2.8. sharpness improve at f/4, and not a big problem f/5.6 and beyond. The color is overall a bit pale. This characterist, however, make it a very good portrait lens. Thanks to the 9-blade aperture, the bokeh is also quite nice.

The ATX 828 is very well constructed. It's solid and feels like a tank. The inner focus mechanics is a very nice design, and only a small lens-group move inside the lens when it is focusing.... it's particular usful to the Pentax AF system: the camera body doesn't have to try too hard to move the lens elements, and the overall AF speed is quite nice.

My only complain is the stupid AF/MF switch of the ATX828 - at AF setting, you cannot manual focus the iens (even with the camera body set at MF). You have to switch to MF mode, which is very clumsy: you need to turn to the right position, then pull back the focusing ring. The 'right' position is different everytime, depends on where was your last MF distance. How stupid!! Imagine when you need to fine-tune the camera's AF.... IT SUCKS! Well, you can always put the focusing ring to the MF position, but then the focusing ring will turn with AF, and also slow down the AF speed. The focusing ring is very well located on the lens, and if it turns during AF, it will affect your handling of the lens.

Legendary Bokeh of FA77/1.8

Just test FA77/1.8 at the 64 candle night memorial. Really love the legendary bokeh of this little jewel. (All photos taken with istD, at ISO 3200. Converted to b/w in Photoshop)









The other photos are here.

Kid shot with DA21, again

I have to admit, I really love this lens. Small and handy, fast focusing, very nice image.

The f/3.2 is not a big problem, it's actually only 1/3 stop smaller than a f/2.8, but the f/3.2 in the DA21 is very usable.

Pentax AP 50 anniv.

Reported by DC Watch.

Are the Pentax management still dreaming about their glorious history? Come on, old man! Wake up and put-up something really matches the modern day demand..... PLEASE!