All Forum Comments
Comment by Mongoose posted on Ebay prices, its a lottery at 29/05/2008 - 01:11
good grief, I paid £20 for one of those a couple of months ago and got a free SF7 with it.
Its a handy lens to have kicking about, but it's not F-70-210 good by any stretch.
Its a handy lens to have kicking about, but it's not F-70-210 good by any stretch.
Comment by Mongoose posted on Ebay prices, its a lottery at 23/05/2008 - 11:05
Quote:
although it can transfer to the sensor when the shutter fires so it's worth using a blower to keep the mirror box in general as dust free as possible.sockpuppet wrote:
I decided to put in a split screen focus from ebay as all of my macro lenses are manual focus and once done realised I had loads of dust in there.
After all that I then took it out as it was truly awfull, the top part of the split kept going really dark.
Your in a muddle . Chris was refering to your sensor not your focus screen. Rubbish on your focus screen won't show up on your pics Quote:
You also need to clean your sensor!!
Waiting for a rocket blower to arrive.You also need to clean your sensor!!
I decided to put in a split screen focus from ebay as all of my macro lenses are manual focus and once done realised I had loads of dust in there.
After all that I then took it out as it was truly awfull, the top part of the split kept going really dark.
Comment by Mongoose posted on Down on the beach .. and not a macro shot in sight. at 23/05/2008 - 10:22
nice spot, that's on my watched list
Sockpuppet you lucky thing!
Sockpuppet you lucky thing!
Comment by Mongoose posted on PKA Adaptall Mount at 23/05/2008 - 10:17
Quote:
It is like building a tank with armour only on the front. It is only as good as its weakest part.
encourages the army not to run away thoughIt is like building a tank with armour only on the front. It is only as good as its weakest part.
Comment by Mongoose posted on DA 17-70 f4 at 22/05/2008 - 10:55
Quote:
I understand the Pentax 16-45mm F4 is really an F2.8-4 lens, but with a cam mechanism to stop it down to provide the constant F4 max ap.
It is therefore not extraordinary that Photozone find its peak resolution is F5.6 at 16mm, and F8 at 45mm. (Center & border averaged).
this is how all constant and near constant aperture zooms work. Since f/ number is the ratio between focal length and aperture, both have to change in concert to keep constant f/4 (or 2.8 or whatever).I understand the Pentax 16-45mm F4 is really an F2.8-4 lens, but with a cam mechanism to stop it down to provide the constant F4 max ap.
It is therefore not extraordinary that Photozone find its peak resolution is F5.6 at 16mm, and F8 at 45mm. (Center & border averaged).
IIRC even the modest FA28-80 3.5-5.6 stops itself down at the wide end when "wide open".
If it didn't, a lens which is f/5.6 at 80mm would of necessity have to be f/2 at 28mm.
Comment by Mongoose posted on MTF data at 23/05/2008 - 11:47
Quote:
Thank you for your responses. On reflection I should perhaps rephrase my question - if there is an MTF programme then presumably the K20D will have been programmed with the MTF data for the relevant lenses.
So what I was wondering was whether there was a database with the MTF details that vthe K20D is programmed with?
each Pentax lens from the F series onwards contains a ROM chip which has (among other things) the MTF data stored on it. The camera acceses this data via the digital data contact on the lens mount.Thank you for your responses. On reflection I should perhaps rephrase my question - if there is an MTF programme then presumably the K20D will have been programmed with the MTF data for the relevant lenses.
So what I was wondering was whether there was a database with the MTF details that vthe K20D is programmed with?
this way, the camera doesn't have to be updated every time a new lens comes out, it simply asks the lens.
Comment by Mongoose posted on MTF data at 22/05/2008 - 13:02
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The A 50mm 1:1.7 lenses were quite fragile.
in what respect fragile George? mine seems very solid and well made, is there a weakness in these lenses I should watch out for?The A 50mm 1:1.7 lenses were quite fragile.
I only ask because mine tends to kick around in the front pocket of whatever camera bag I'm carrying (it's so small I see no reason to ever be without it). It hasn't come to any harm so far but if they are more fragile than they seem perhaps I should be nicer to it.
Comment by Mongoose posted on When is a Pentax not a Pentax? at 20/05/2008 - 11:46
Quote:
Do you have the dedicated ME-F 35-70 lens too ?
/Ian
Alas, no. I've never managed to pick up a working example. I understand that the AF isn't particularly good and munches batteries like there's no tomorrow, but it would be nice to get hold of one to complete the set.Do you have the dedicated ME-F 35-70 lens too ?
/Ian
I originally bought the ME-F because at the time I was an impoverished undergrad student and ME-Fs tended to sell for less on ebay than ME-Supers.
I have grown to love it and it's MF assist function is a nice perk even without the matching AF lens.
Comment by Mongoose posted on Back to the old(ish) School at 22/05/2008 - 13:07
At up to £25 I wouldn't think twice, much more than that and you have to start asking some serious questions.