Saxat ifrån Dpreview:
The Zenitar is a "manual" lens. You focus manually and you read the light manually. These are both quite quick operations.
Focusing:
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1: Set the camera lever for focusing method to MF
2: Focus by turning the distance scale and watch what happens in the viewfinder
3: You'll have a huge DOF (Depth of focus) thanks to the short FL (Focal Length).
4: Initially it seems hard to set the focus but with some training it comes quite easy and quick
NB: With focusing set to AF the shutter won't go off when pressing the release button. Well, sometimes it does - that is when the "focus confirmation function" thinks you have set the focus correctly. This is slow and unreliable. With the camera set to MF you override the function and can exposure at will.
Light metering:
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Camera: *ist DS (but probably all the cameras in the digital *ist series. For the first model, the plain "D" the AE-L button = the green button).
The Zenitar has an aperture ring. Checking the ring you can see that there is no "A" position on it. In other words: no automatic light metering! You have to do this yourself. Metering the light manually gives you control of things. And puts you in charge. When taking several pictures at the same time you don't need to meter the light for every picture. If the light doesn't change the exposure values remains the same. Follow these steps to get started:
Prepare camera:
1) In the camera setup, in Customs menu set the option "Using aperture ring" to "2".
2) In the camera setup, in Rec. Mode menu set the option AE Mode to either Spot or Center weighted
3) Focus mode to MF
a) Dial in the desired aperture by turning the aperture ring
b) compose
c) turn the camera on, or make it active by half pressing the shutter release a moment
d) compose and aim the camera properly (depending on your choice of Spot or Centerweighted metering) and press the AE-L button for a second
by diong this the camera stops down (the aperture is for a moment set to the same opning it will have when taking the picture)
during this moment the camera meters the light and sets the aperture time to fit with the ISO, aperture and light conditions at place
e) recompose if necessary, check focus
f) press the shutter release button
Now you have taken a z-picture
Let's elaborate on this a little. The setting 1) above cn be left at "2". There is no need to turn it back to not allow use of the aperture ring. All other lenses will work fine with the setting above. With this setting lenses with an A position on their aperture rings can be used with the ring in other positions than A. If you by mistake move the setting from A on the aperture ring the camera functions but ypu will probably get a bad exposured picture. I don't think this is a big deal. You won't change the setting on the perture ring by mistake without noticing it that often.
For point a) - see the USAF cards. Preferably use f5.6, or F8. F4 and F11 are okey, they are nearly as sharp. Avoid F2.8, F16 and F22. (This is btw true for most lenses.)
For point b) - is pays off to think about what you are aiming for when taking the picture. If you are aiming for a rectilinear wide angle picture you should try to keep important lines (the horizont, a building) as centered as possible. If you are looking for the fisheye effect things are different. Practise. Learn to know your equipment.
For point c) - there is a setting in the customs meny allowing you to choose for how long time the meter shall stay active (=on) after you have fiddled with the camera. Chosse between 3, 10 and 30 seconds. Yes, the correct answer is 30 seconds. Imo that is the most conveniant setting as it take a second extra to get things going every time the camera turns itself off. It's no big deal though.
For point d) - remember the word "Manual". The exposure is set by manual intervention. If you don't change anything everything is the same. Recompose and nothing happens. Turn the camera off for having lunch and turn it on again, nothing is changed. Changesettings by turning the thumb wheel (shutter time) or the aperture ring (doh, fo rthe aperture opening). For making a new reading of the light, once again press the AE-L button.
For point e) - remember the DOF. I sometimes set the distance scale to a value between 1.2 meters and infinity and the aperture ring to F8. Now everything between 1m and the moon is in focus.
All of the above is valid also when it comes to Pentax M and K lenses.