[stupido]

Stapler,

I have a Zenitar 16mm. I like it. The links below have some pics I took years ago. Its a nice lens but I don’t use it much.

Also I got the original screw mount version. It will not stop down on a K-mount camera.

http://64.253.97.239/zenitar/zenitar.htm
http://64.253.97.239/panama/2000nov/2000nov.htm

[stupido]

Pentax Stuff

The *istD was the top of the line Pentax. The *istDL is the entry level. I have the *istDS.

The DL has a pentamirror. The DS and D models have a pentaprism. All use the same sensor. There are firmware differences etc. Basically, Pentax has deleted a few features on the *istDS as to make it a medium range camera. The *istDS2 is basically the same as the *istDS but with a larger LCD. All the *st cameras use the same Sony sensor and Pentax shutter.

I have not looked at the K10D, K100D and K110D.

The advantage of the Pentax is the extremely large variety of used lenses. Used screw mount and Kmount lenses are dirt cheap. Also the build quality seems to be better than the entry level Canon.

In all I have been very happy with my *istDS. Of course I have a large collection of Pentax and Pentax mount lenses.

[stupido]

The scientific answer ain’t too bad. The F-stop is the ratio of the focal to the diameter of the opening. If you double the focal length (zoom in) you double the F-stop. Wiki has an nice article:

http://en.wikipedia.org/wiki/F-number

But really, just remember, as zoom in, you cut the amount of light you are receiving and thus the F-stop number increases.

[stupido]

Monkeybort,

OK, you are a MAC user. Find a friend with an older PC (win98) and a card reader. The card should be FAT since that’s what most cameras use. The lock might just be related to the MAC OS. Can the camera be used as a drive with the MAC? If so try that too.

[stupido]

Monkeybort,

One thing to try is to use an alternative OS. Linux or DOS or Win98. The point would be to use an OS which does not care about the lock.
Which OS are you using? Additionally there are serveral recover tools available too.

[stupido]

I found that in touristy areas most the time they don’t even know you are taking a pic of them instead of the bridge, beach etc.

Another good location to take pictures is demostrations. Most want thier pics taken. Probably not a good idea to take a picture of the anarchists though.

[stupido]

For first roll with Diafine:

I do need to get a wetting agent for the rinse as the streaks have driven me nuts. But still cool

Some of the scans.
http://www.flickr.com/photos/mariser/sets/72157594161061944/
http://www.flickr.com/photos/stupido/sets/72157594161065244/

[stupido]

What are the options for Dye-Sub printers on B&W?

[stupido]

Quicker wat to think.

LCD screens are polarized. Assume vertical.

You have adjusted the circular polarized to vertical.
It is not blocking any of the LCD light. The second layer
divides the light so it is half vertically and half horizonally polarized.

Now you you adjust the linear polarizer to horizonal. It blocks all of the normal LCD light. But half the light through the circular polarizer is now horizonal and makes it through the linear polarizer.

[stupido]

Hi. I was fooling around with some polarizers and my LCD when I noticed I could do this:

There’s a linear polarizer on the camera blocking out light from the lcd, then a circular polarizer in my hand sneaking light in. What on earth is going on and how can I use this weirdness to my advantage?

(sorry for the low quality, I’m tired, drunk and impatient)

From what I read, a cicular polarizer is a regualr polarizer plus a secondary layer to de-polarize the light. The light that reaches the camera is supposed to be evenly split between vertical and horizonally polarized light as not to mess with the filters.

So what you are seeing is half the light from the LCD.

Basically, you have rotated the cicular polarizer so that its aligned with the polarized light of the LCD. IE, its not blocking anything. Now, the second layer is changing the polarization of some of the light. Thats what gets through the linear polarizer. From my reading it should be half of the LCD approximately. Assuming a lot of crap.

Probably the best example of how a circular polarizer works.

[stupido]

Stapler,

One of the problems with autofocus lenses, is that the focus mechanisms are loose. This enables the motors to drive the lenses.

Another problem is most autofocus cameras do not have the split prism circle either.

So bracket your focus zones like you would exposures. Stop down if you don’t need shallow depth of field etc.

Is the 50mm easier to focus? I would imagine it is.

You could always mount a pure manual lense.

Have fun.

[stupido]

Well, if one wants to ‘shop my pics, here’s my license:

Tell me
Give me credit
tell me the link

Pics are mainly at:

http://www.saracom.com
http://www.flickr.com/photos/stupido/
http://www.dotphoto.com/go.asp?l=cookie%5Fkeith&p=ADF3

Ask and I will give you high res if possible. Some are low res scans.

[stupido]

Tamron AF 28-75mm f2.8 becomes:
39 – 105 f/4 with a 1.4x
56 – 150 f/5.6 with a 2x

Canon EF 50mm f/1.4
70mm f/2 with a 1.4 x
100 f/2.8 with a 2x

Canon EF 70-200mm f/2.8L
98 – 280 f/4 with 1.4x
140 – 400 f/5.6 with 2x

You have reasonably fast lenses so the converters wont hurt too much.

[stupido]

You lose both f-stops and quality.

The f-stops is simple. A 2x adds 2 stops and a 1.4 adds 1 stop (rounded). This is due to the fact that you are changing the focal length while keeping the lense diameter the same. F-stop is Focal length/diameter. So if you have a F/2 lense it is now a f/2.8 with a 1.4x and a f/4 with a 2x.

Here is the modern f-stops:
f/0.7, f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128

So if you have a zoom which is f/5.6 on the long end (common on the bundle lenses) it would be a f/11 with the 2x at the long end!

As far as quality, you add glass surfaces so it will hurt some. A 200mm lens usually will outperform a 100mm with a 2x.

Any way I have used a 2x with my Pentax and Zenit cameras and I am happy with it. I actually have used a 3x with a 300mm prime before too and was happy with the results.

[stupido]

They’re pretty much standard filter sizes, and fit standard filter threads (my set of Hoya lenses are about 20 years old) so you can use them on any lens with the same filter diameter (unless you use step rings, but that’s a different topic)

For 55 mm you’d by this set:

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=22747&is=REG&addedTroughType=categoryNavigation

Thanks 😀

You can also buy filter adaptors to adapt them to other thread sizes. They are called step up or step down adaptors. When you buy one, you buy it from the lens perspective and not the filters.

IE, if you had a lens with a 52mm thread size and a 55mm filter (or close up adapter) you would need a 52 to 55 mm step up adapter.

Stepping up is usually not a problem. Stepping down can be especially with wide angle lenses.

[Author]

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