All Forum Comments
Comment by petrochemist posted on Tamron 200mm/3.5 incl PKA adapter for sale at 04/01/2011 - 23:06
http://www.butkus.org/chinon/pentax.htm
Anything else, if you make a specific request for it, you might find someone who has one they'd be willing to copy.
If you want originals then I rather doubt anyone will have them to give away - they are often sold on e-bay. Sometimes the e-bay ones are just print outs of downloaded manuals anyway!
Comment by petrochemist posted on I'm looking for Pentax booklets at 03/01/2011 - 14:45
http://photojojo.com/store/awesomeness/camera-lens-mug/
And thought at last a proper use for them
Needless to say Pentax lenses are too good to convert!
Comment by petrochemist posted on Finally a decent use for CaNikon lenses at 03/01/2011 - 11:53
How's the iq on that bad boy, and what are the specs / make?
Apparently it's f16 at 1000mm (x15) & f64 at 4000 (60x). Of course there's no adjustable aperture.
IQ isn't brilliant, but that may be partially poor focusing. (It looks much brighter/sharper without the camera mounted.) I rarely use it zoomed beyond about 1500mm as the image is too dark to focus.
A couple of shots in my portfolio where made using it see:
https://www.pentaxuser.com/photo/user-10694/powerboat-marshal-23124
https://www.pentaxuser.com/photo/user-10694/ocr-powerboats-20669
Several more are in my Flickr stream (Most of the powerboat shots))
Comment by petrochemist posted on 1000mm at 02/01/2011 - 17:43
But with the limited feedback history & no images of the optics no thanks.
Besides my 1000-4000 scope is only two stops slower at the wide end, and only cost 1/10th as much
Comment by petrochemist posted on 1000mm at 31/12/2010 - 18:33
1. A fish eye converter from a car boot sale, which has proved fun enough to be worth the £12 it cost, but rather disapointing compared to proper fisheye lenses.
2. A 2* adapter. This has proved to be a complete waste of £10! It does bring things closer, and allows continued use of autofocus & auto aperture (as the lens still mounts directly on the camera) BUT the IQ is awful, it vignetts badly below ~35mm, it increases the minimum focusing distance by 2.5 fold, and so reduces the acheivable macro magnification.
Ordinary teleconverters (even ultra budget ones) are much better, though these days second hand lenses are available cheap enough to make these the use of these rather limited too.
Comment by petrochemist posted on additional lenses at 30/12/2010 - 16:41
Of my current collection of tripods there are 2 that get used - a light & cheap (£12 new) one from 7-day shop for carry around light use & a second hand Manfrotto (~£150 with the head) for studio/digiscoping.
The cheap ones worked out remarkably well, but it's not really rock steady & won't reach my eve level (I've never tried the central pillar - they're generally to unstable)
The Manfrotto is easy to adjust, goes well above my head (possibly to over 2.5m) and is rock steady. But you know about it after carrying it quarter of a mile.
When funds allow I hope to add a Benbo style one to the collection...
Comment by petrochemist posted on Big, strong, cheap, and light tripods? at 28/12/2010 - 21:42
If you can get to them I definitly think it's worth a try
Comment by petrochemist posted on K10D four-way arrow switch replacement at 26/12/2010 - 09:52
Prime focus with no lens/eyepiece (called negative projection it a barlow is added)
Postive projection with eyepiece but no camera lens
A-focal using both an eyepiece & a camera lens (often a compact camera or even web cam)
I can't help wondering if it's not possible to use a camera lens with no eyepiece but I've never seen this permutation mentioned.
With my Newtonian it seems I have to get the camera into the telescope tube to achieve infinity with prime focus, & I've never managed to nail the focus when I've tried positive projection either - here it is slightly beyond the focus range but with the eyepiece only partially inserted or with an extension it should be possible to achieve focus eventually.
All I really need now is several years of comfortably warm, clear, dark nights (on which the kids have gone to bed...) to practice technique. Then I should be able to get close to Teds results. His scope is better for this but for the moon that shouldn't be an issue.
In the meantime I'll keep reading tips on technique.
Comment by petrochemist posted on Moon Shot at 25/12/2010 - 22:33
http://flic.kr/p/94rsAe
[img]http://flic.kr/p/94rsAe
[/img]
" class="comment_image" />Comment by petrochemist posted on Show us your xmas tree. at 25/12/2010 - 14:08

