Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
09-17-2011, 01:38 PM   #16
Senior Member




Join Date: Jun 2011
Photos: Gallery | Albums
Posts: 160
Original Poster
QuoteOriginally posted by JeffJS Quote
Do you mean f8? Most mirror lenses Are f8. Here's the thing about Mirror lenses. Most, if not all, have NO apertures. In order to 'adjust' them, you need a ND filter on the rear. Some lenses come with them, ND2, ND4 so make sure if you buy one you get the filters as well. These are 30.5mm filters in most cases and can be a little difficult to find separately. There is also a UV filter that is typically installed on the lens rear. A filter Must be on the lens or it won't focus. I would check Ebay. $130 sounds expensive for anything BUT the Tamron SP 500mm f8 (then it's Cheap) in my experience for Just the lens. Nothing is free so when you want to stay within a budget, there are going to be compromises.

500-1000mm TELEPHOTO Lens for Pentax K-5 645D K20D K10D | eBay


No I meant f6...this was the thread I was talking about
As you will see it says f6.3 so technically I wasn't right either but thats besides the point.
I was pm'ed a suggestion of a manual sigma 400mm apo lens so i'll just follow it and see how that goes along with a continued search for a possible alternative to these apparently rare and expensive TCs. Thanks.

09-17-2011, 02:43 PM   #17
Veteran Member
RioRico's Avatar

Join Date: Jun 2008
Location: Limbo, California
Posts: 11,264
A comment: The jump from 300 to 400 isn't as significant as it sounds; it's rather like going from 105 to 135. (I just did a comparison.) If you're looking to stretch from 300, think more of 500+. Now, if the 400's optics are clearly better than the 300's, it's a no-brainer -- jump. But if they are comparable, you might be disappointed at not getting more reach.

Thus, mirrors. Some cheap ones aren't good, some are. (My Sakar 500/8 costing US$13 shipped is OK.) Really decent ones needn't be too expensive. Russian mirrors are prized. True, mirrors have no aperture mechanisms. I don't use ND filters; mirrors are slow enough that exposure can be controlled well enough with just shutter and ISO adjustments.
09-17-2011, 02:49 PM   #18
Senior Member




Join Date: Jun 2011
Photos: Gallery | Albums
Posts: 160
Original Poster
QuoteOriginally posted by RioRico Quote
A comment: The jump from 300 to 400 isn't as significant as it sounds; it's rather like going from 105 to 135. (I just did a comparison.) If you're looking to stretch from 300, think more of 500+. Now, if the 400's optics are clearly better than the 300's, it's a no-brainer -- jump. But if they are comparable, you might be disappointed at not getting more reach.

Thus, mirrors. Some cheap ones aren't good, some are. (My Sakar 500/8 costing US$13 shipped is OK.) Really decent ones needn't be too expensive. Russian mirrors are prized. True, mirrors have no aperture mechanisms. I don't use ND filters; mirrors are slow enough that exposure can be controlled well enough with just shutter and ISO adjustments.
Yeah I was thinking about how big a difference 300 to 400 would be and have been looking into mirrors and some with TCs to extend the range even further. Yeah I probably won't be using the ND filters much if at all. Thanks.
09-18-2011, 01:15 PM   #19
Senior Member




Join Date: Jun 2011
Photos: Gallery | Albums
Posts: 160
Original Poster
For anyone interested I ended up buying a Opteka 500mm f/8 mirror lens with a 2x TC, 3 filters, a soft carry pouch, front and back lens caps, and t mount adapter for just under $100 shipped. I mainly chose this over other options b/c it came with a 10 year warranty.

09-22-2011, 03:20 AM   #20
Pentaxian
kh1234567890's Avatar

Join Date: Sep 2010
Location: Manchester, UK
Photos: Gallery
Posts: 2,406
QuoteOriginally posted by JeffJS Quote
A filter Must be on the lens or it won't focus.
Not in my experience : Super Paragon 300mm f5.6 Mirror Lens SmartSet - a set on Flickr

It is a totally unsubstantiated internet myth.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
2x, 300mm, af, k-mount, lens, pentax, pentax lens, price, slr lens, tamron, tc, teleconverter, vivitar
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tax and spend repubs..opps.. just spend. jeffkrol General Talk 31 07-01-2010 03:23 PM
Spend $200 on a new Pentax macro or wait? MoparFreak69 Pentax DSLR Discussion 3 07-22-2009 11:28 PM
Lens money to spend steve917 Pentax SLR Lens Discussion 3 05-10-2009 08:23 PM
Help me spend money: on a lens liberiabound Pentax SLR Lens Discussion 7 03-18-2009 02:20 PM



All times are GMT -7. The time now is 07:40 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top