Forgot Password
Pentax Camera Forums Home
 
Log in or register to remove ads.

Showing results 1 to 10 of 10 Search:
Forum: Lens Clubs 04-10-2012, 05:32 PM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
No problem. Hope it helped! ;)
Forum: Lens Clubs 03-24-2012, 05:58 AM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
You'd do much better buying a used Tokina, Tamron, or Sigma with a Pentax mount. Those new "generic" brand ones (also labeled as Rokinon, Polar, Bower, etc.) are generally not built as well as these older ones, and once the mirror gets out of alignment, there is no saving the images from that lens!

EDIT: in fact, if you check eBay you can get one for very little. (I have the Tokina, and it's pretty good with the rear filter in)
Forum: Lens Clubs 02-13-2012, 05:42 PM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
You want to get close-up photos of the other peaks? Mirror lenses are much lighter and more compact than the equivalent zoom or prime telephoto, but aside from the "donut halos" they are also temperature sensitive due to deformation of the mirror when going from warm-cold-warm, etc. So, a mirror won't be useful for the first 30 minutes of your hikes, and frankly they aren't as rugged as "regular lenses" if you drop them or bang them about (this depends on the maker of the lens, of course). It's a toss-up, but I completely understand the desire to pack light up there! :p
Forum: Lens Clubs 02-09-2012, 03:27 PM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
Are you using phase detect AF or Live View (CDAF)? I put my AFA on the Tokina 500mm/8 and it did nothing but hunt around using phase detect AF, even in bright light. However, the CDAF of Live View (K-5) was pretty good and fairly quick... but this was on a tripod on a sunny day!
Forum: Lens Clubs 11-10-2011, 12:00 PM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
Let's hope! (And thanks for the scans of the manual - mine was without...)

So, I finally had some time and no rain, and did "the test" as best as I could do it. That meant my best tripod w/ weight hanging from it, SR off, MLU, wired remote, focusing w/ Live View, and very carefully adding the filter into the mix.

Here are the results:
Both with Tokina 500mm, f/8 (where else?) 1/350 @ISO 800, converted in ACR with no adjustments and same 100% pixel crop for both.

WITHOUT FILTER (Click for full-size, pixel-to-pixel image)



WITH TOKINA 35.5mm "Skylight" FILTER (Click for full-size, pixel-to-pixel image)



Now I'm not entirely blind, and there are definite optical differences here (color, magnification, OOF highlights) but sharpness doesn't seem to be one of them. I can probably be convinced otherwise, but this isn't as dramatic as I'd feared.
That being said, I'll leave the filter in there, since the manual said to and it's one less thing to lose. It also seems that my previous (not so spectacular) results might have been from a temporary temperature deformation of the mirror, or my CF tripod not having extra weight under it.
Forum: Lens Clubs 11-05-2011, 06:48 AM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
This is pretty much what I thought, but rather than silently test it (and probably still wonder), I'm glad to get constructive input from others.



This actually sounds much more likely, as it is now below freezing in the AM here, and I don't leave my lenses on the porch overnight! If I get some time, I'll do a filter/no filter test with the lens at equilibrium.
Forum: Lens Clubs 11-04-2011, 11:38 AM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
Your shot looks much sharper than mine, and outdoors as well!

Something that just occurred to me (and maybe the mirror-lens gods will help here) is that I removed the rear filter that was screwed into the back of my Tokina. It is clear glass - is this required as part of the optical formula?
Forum: Lens Clubs 11-01-2011, 01:39 PM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
In your opinion (or anyone else's for that matter), does the indoor shot from that same mirror at the top look "sharper" to you? That's what confuses me! It seemed like a different lens outside... :eek:
Forum: Lens Clubs 11-01-2011, 09:25 AM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
Hi Mis. Yes, the lens hood was on, and I chose that shot from a series that were in/out of focus. I judged the focus by the tree branches and stems, which seem to be sharp enough at high contrast edges, but the texture of the tree and leaves is completely absent. Perhaps I am expecting too much contrast from a mirror... I'll try some post-processing tricks to bring up local detail.
Forum: Lens Clubs 10-29-2011, 06:21 PM  
The Mirror Lens Club!
Posted By panoguy
Replies: 1,239
Views: 467,213
Just picked up one of these Tokina mirrors from the marketplace, and so far I've been both impressed and confused. Impressed by just how small and light it is for a 500mm lens (shorter than my Tamron 17-50mm), and confused by how it is pretty sharp indoors at low shutter speeds yet soft at larger distances outside.

As far as "long lens technique" goes, I'm new to this and I've found focusing much easier with a zoomed-in Live View, and I do use a solid Feisol tripod with Markins ball-head, and turn SR off. For the outside shots, I even used MLU and a wired remote with shutter speeds over 1/750.

Am I expecting too much by comparing this to the DA 55-300 (and cropping)?

Photos below (all 100% crops), focused center of frame, near the top:




**I was focusing on the trunk of the tree, using the fence as a focus check.**
Search took 0.00 seconds | Showing results 1 to 10 of 10

 
Forum Jump


All times are GMT -7. The time now is 06:05 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