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johnriley

Joined: 19th March 2002

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johnriley
Quote:
Obviously they mustn't have checked if the lens needed AF adjustment before doing the tests
That's an interesting point - should the reviewer have to fine tune something sent from a manufacturer or is his/her job to test what has been sent, as-is?

Comment by johnriley posted on A few q's about the Sigma 30mm, eBay and Sigma sevice before I buy... at 29/05/2011 - 11:47

johnriley
Quote:
It's not that 1.4 lenses are difficult to focus it's that at apertures like 1.4 the viewfinder can't show a DOF that narrow, so you can be out of focus even though it looks in focus through the viewfinder.

I showed this effect to a shooting buddy recently with my Pentax A 50/1.2. I got him to look at and focus on a subject @ f/1.2 and asked him note teh DOF in the viewfinder and then note the DOF in the actual picture taken in the preview screen. he was actually shocked at the difference.

We're talking about two different things. In any event it's impossible IMHO to judge DOF from the viewfinder, or from the back screen either, because they are both too small. Turn it into an A3 print and we're in a different ball game.

This is why if I'm going for maximum DOF I use the, say, f8 markers on a lens but actually set the lens to f11. This of course assumes that the lens does actually have DOF indicator markings. Most manual focus ones do. Most zooms do not.

Comment by johnriley posted on A few q's about the Sigma 30mm, eBay and Sigma sevice before I buy... at 29/05/2011 - 10:56

johnriley
I'll leave the thread as a record of this, but lock it.

Comment by johnriley posted on FS: FA 31mm Limited in Black - mint at 29/05/2011 - 00:27

johnriley
That part too is available from SRS.

Comment by johnriley posted on WTB: Flash Sync cap at 29/05/2011 - 00:20

johnriley
As you've got a special edition it might be best to return it to JP Solutions under warranty. Once fixed I'm sure things will be fine, although it's very frustrating when things go wrong.

Comment by johnriley posted on K-5 Silver... Crashed at 28/05/2011 - 16:51

johnriley
I'd suggest not using auto ISO. I always set a fixed value so that all images will have the same noise structure. ISO can be adjusted manually very easily if needed.

Comment by johnriley posted on K-5 Over-Exposure with flash at 28/05/2011 - 16:42

johnriley
I'm surprised that people are using such high ISO values with flash. With studio flash we would be using ISO100 or ISO200 and getting apertures from f8 to f16 depending on the setup.

If the ISO is too high there is no aperture small enough to expose correctly.

Comment by johnriley posted on K-5 Over-Exposure with flash at 28/05/2011 - 14:15

johnriley
Quote:
The 43mm Ltd was supposedly made because Pentax decided the proper standard lens for 35mm cameras was around the 40mm mark
Almost right. The "standard" lens for a format is traditionally considered to be the diagonal measurement of that format. The diagonal for a 36x24mm frame measures just about 43mm. Pentax have been the only manufacturer as fara sI can tell who have made a "true standard" for the 135 film format.

However, early lens making also took its traditions from Leica, which used available cine focal lengths, so 50mm was widespead. Something slightly longer is easier to make, so 58mm was often used for wide aperture standard lenses.

Relating this to the real world, a "standard" lens is one that comes closest to showing a scene as our eyes see it.

Comment by johnriley posted on Do we think there's any chance... at 28/05/2011 - 14:11

johnriley
Anyway, back to the point. Does anyone have a flash cap for our OP?

Comment by johnriley posted on WTB: Flash Sync cap at 28/05/2011 - 13:25

johnriley
I don't lose the pouch because it's an antique - my mother's wedding ring came in it in 1950.

For my business cards I use a small leather wallet from around 1915, which also has spaces for stamps that happen to be exactly the right size for SD cards.

For any AA batteries I have a flip top container that housed cufflinks and is exactly the right size for 4 AA batteries.....

Comment by johnriley posted on WTB: Flash Sync cap at 28/05/2011 - 13:24

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