Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
01-18-2013, 10:38 AM   #1
Site Supporter
colonel00's Avatar

Join Date: Nov 2012
Location: Shawnee, KS
Posts: 468
Help a noob relate the reach of a spotting scope to that of an adapted Q

I decided to put this in the Q forum as I think Q users might have good insight. If it better fits somewhere else then please move it. Thanks.

As I plan to start my adventure into the world of DSLR I have settled on the K-30 with the 18-135mm kit. I also plan to pick up the DA 55-300mm fairly quickly too. However, the Q has also caught my eye with the fantastic shots people are getting with adapted lenses. Because I am an avid outdoorsman and hunter, I have also been planning to upgrade my optics with a better spotting scope but something I can still hike with. Recently I have been looking at the Vortex Viper HD 15-45x60. Vortex makes a slick adapter to allow for digiscoping and such so this would work for me as well. Unfortunately, this is turning into quite a bit to carry should I be out on a long hike. I would definitely want to have both the 18-135 for weather concerns and the 55-300 for its reach as well as the spotting scope for hunting/scouting.

Now, here is my question. Let's say I pass on the spotting scope and use a Q with the 55-300, how would that compare in reach to the spotting scope? What about with a TC? I realize that I may be losing some quality but would it still be somewhat functional as a make shift spotting scope? I don't expect it to be the same image quality or reach as the spotting scope but I am having a hard time getting my head around how the two setups would compare.

Being that I want to keep this to a simple, light kit, is the 55-300 the best option? I know everyone loves the DA*300 but that is a bit pricey for me and would just be another large item to carry.

I know this is kind of an obscure question but hopefully someone can help me understand how the 15-45x60 of the spotting scope would compare to the Q + 55-300mm. Moreover, I think I am most interested in the long end of each so the scope at 45x60 and the Q at 300mm. Thanks.

01-18-2013, 10:46 AM   #2
Veteran Member
Docrwm's Avatar

Join Date: Sep 2010
Location: Somewhere in the Southern US
Photos: Gallery | Albums
Posts: 11,275
The 55-300 ends up being ~300mm to 1650mm on the Q.

For every 50mm of focal length you get 1x of power. What this means is, a 200mm lens is 4x. A 300mm lens is 6x and a 500mm lens is 10x. That means you'll get roughly a 33x out of the 55-300 at 300 on the Q.
01-18-2013, 10:48 AM   #3
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
I have not used that scope but used to own a Pentax PF-80ED. I believe I heard that it was comparable to a 1000mm camera lens as far as range.
Your 55-300 will give you somewhere around 300-1650 mm equivalent, a slong as you don't mind looking at an LCD screen. You can also add a lcd loupe but it may get bulky.
I think for photos it is worth the effort, but as just a viewing device it may not be the handiest.

Have you looked into the Kenko lens to scope adapter? I have only read info on the internet but it may be a solution for a smaller kit.


Review of Lens2scope spotting scope adapter – and a warning
01-18-2013, 11:11 AM - 1 Like   #4
Pentaxian
pete-tarmigan's Avatar

Join Date: Apr 2009
Location: Conception Bay South, New-fun-land
Photos: Gallery
Posts: 1,007
QuoteOriginally posted by crewl1 Quote
I have not used that scope but used to own a Pentax PF-80ED. I believe I heard that it was comparable to a 1000mm camera lens as far as range.
Your 55-300 will give you somewhere around 300-1650 mm equivalent, a slong as you don't mind looking at an LCD screen. You can also add a lcd loupe but it may get bulky.
I think for photos it is worth the effort, but as just a viewing device it may not be the handiest.

Have you looked into the Kenko lens to scope adapter? I have only read info on the internet but it may be a solution for a smaller kit.
The PF-80ED has a focal length of 1000 mm when used with the Pentax PF-CA35 adapter, the latter of which forum member "Falco" says acts as a 2X teleconverter. With a T-mount adapter (containing no glass) this scope would therefore have a focal length of 500 mm. According to marketing material the PF-65ED and PF-100ED scopes have different focal lengths than the PF-80ED. The focal lengths of other brands would probably vary in similar ways.

01-18-2013, 11:20 AM   #5
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
QuoteOriginally posted by pete-tarmigan Quote
The PF-80ED has a focal length of 1000 mm when used with the Pentax PF-CA35 adapter, the latter of which forum member "Falco" says acts as a 2X teleconverter. With a T-mount adapter (containing no glass) this scope would therefore have a focal length of 500 mm. According to marketing material the PF-65ED and PF-100ED scopes have different focal lengths than the PF-80ED. The focal lengths of other brands would probably vary in similar ways.
Thanks for the clarification Pete
01-18-2013, 02:58 PM - 1 Like   #6
Senior Member




Join Date: May 2012
Posts: 165
Lens2Scope

QuoteOriginally posted by crewl1 Quote
I have not used that scope but used to own a Pentax PF-80ED. I believe I heard that it was comparable to a 1000mm camera lens as far as range.
Your 55-300 will give you somewhere around 300-1650 mm equivalent, a slong as you don't mind looking at an LCD screen. You can also add a lcd loupe but it may get bulky.
I think for photos it is worth the effort, but as just a viewing device it may not be the handiest.

Have you looked into the Kenko lens to scope adapter? I have only read info on the internet but it may be a solution for a smaller kit.

2013 CES - Kenko LENS2SCOPE Adapter - YouTube

Review of Lens2scope spotting scope adapter and a warning
I have a Lens2Scope with a K mount on order from Amazon. I plan to use it with a Pentax M 200mm lens. It will be the equivalent of a 1100mm lens on the Q. With the Lens2Scope, it will be a 20x scope.

This should be a very light, compact, and bright kit.

When the 200mm lens is attached with a K to Q adapter, it is the equivalent of a 22x scope. This is very similar to the 20x view when used with the Lens2Scope.

This kit is much easier to use for both viewing and photography than adapting a spotting scope. It should be brighter as well. It should be easier to focus.

The Pentax PF65 scope with a fixed focal length eyepiece has about a 27x view, but is about f12. One very nice thing about the Pentax fixed focal length eyepieces is that if you remove the eyecup, it reveals a 43mm thread. With a 40.5 to 43mm adapter you could attach the Q with the 01 lens attached. This is the easiest digiscoping setup I have identified.

One advantage the PF65 with the fixed eyepiece is that it is waterproof and field rugged.
01-18-2013, 03:01 PM   #7
Site Supporter
colonel00's Avatar

Join Date: Nov 2012
Location: Shawnee, KS
Posts: 468
Original Poster
Thanks for the replies so far. I think I kind of understand a bit more now.
01-18-2013, 03:07 PM   #8
Site Supporter
colonel00's Avatar

Join Date: Nov 2012
Location: Shawnee, KS
Posts: 468
Original Poster
QuoteOriginally posted by GXRUser Quote
I have a Lens2Scope with a K mount on order from Amazon. I plan to use it with a Pentax M 200mm lens. It will be the equivalent of a 1100mm lens on the Q. With the Lens2Scope, it will be a 20x scope.

This should be a very light, compact, and bright kit.

When the 200mm lens is attached with a K to Q adapter, it is the equivalent of a 22x scope. This is very similar to the 20x view when used with the Lens2Scope.

This kit is much easier to use for both viewing and photography than adapting a spotting scope. It should be brighter as well. It should be easier to focus.

The Pentax PF65 scope with a fixed focal length eyepiece has about a 27x view, but is about f12. One very nice thing about the Pentax fixed focal length eyepieces is that if you remove the eyecup, it reveals a 43mm thread. With a 40.5 to 43mm adapter you could attach the Q with the 01 lens attached. This is the easiest digiscoping setup I have identified.

One advantage the PF65 with the fixed eyepiece is that it is waterproof and field rugged.
Thanks for the great info. I will definitely have to give this a look. I assume you could also get an adapter for a K lens, right? I guess that would be kinda silly though unless I just didn't want to bring a Q with me. Do you happen to have any digiscoping photos as examples?

01-18-2013, 03:48 PM   #9
Loyal Site Supporter
baro-nite's Avatar

Join Date: Aug 2011
Location: North Carolina, USA
Photos: Gallery | Albums
Posts: 4,344
My take on this may be a bit different. I've been doing my best to understand the nature of the advantage the Q can give for super-tele shooting; my level of technical understanding is not high, so take this with a grain of salt.

Ignore crop factor and equivalent focal lengths; they are misleading. What matters is the resolution of the lens and sensor in combination. The keys to the Q are that it has roughly three times the linear pixel density of the K-30 or K-5, and that it uses the center of the image circle, where lens resolution is highest. When you don't have enough reach on the K-30 or K-5 and would need to do a heavy crop, or where you want to make an especially large print, using the same lens on the Q may give you higher resolution on the subject and thus give a larger and/or more detailed final image.

How much more? Less than the 3x increase in pixel density, for several reasons: the Q sensor has lower dynamic range and more noise; it is hard to achieve the precise focus and camera stability required to leverage the higher resolution sensor; diffraction softening begins around f/4; last and most importantly, most lenses simply aren't sharp enough and have too much CA to perform well on the Q. My ballpark guess is that, with the right lens, conditions (including good light), and care, you can achieve most of this 3x increase in resolution, maybe 2.5x.

However, because of the diffraction limit, unless you're starting with an f/2.8 lens you are unlikely to gain anything from adding a teleconverter with the Q, where you might on the big sensor. A lens that performs well on the Q is likely to perform well with a TC, too. A 2x TC and higher ISO (to compensate for the 2-stop light loss) on the K-30/K-5 could reduce the Q's advantage quite a bit. I've done a small bit of testing with a cheap 2x on the DA* 300, and figure (ballpark) that the Q's advantage is down to 1.5x or so. That's still a very significant advantage! It's just a lot less than the 3.7x difference in crop factor, which is really meaningless for this comparison. And it has to be weighed against the disadvantages of the Q: shutter lag, FPS speed, high ISO performance, strictly MF with adapted lenses.

I don't know what resolution one can get from digiscoping, so I can't compare. That's obviously going to be an important question for your decision.
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!
55-300mm, bit, camera, mirrorless, pentax q, pentax q10, pentax q7, plan, q10, q7, quality, question, reach, scope
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Naive question of the day: Any benefit to adding a modern filter to an old lens MSL Pentax SLR Lens Discussion 15 11-17-2012 07:48 AM
Hooking up a spotting scope to a dslr? slackercruster Pentax SLR Lens Discussion 6 03-28-2012 04:45 PM
Using Pentax Spotting Scope as a Lens? Tamia Pentax SLR Lens Discussion 13 02-14-2011 01:17 PM
Which lenses reach the resolution of a K5? peterh337 Pentax SLR Lens Discussion 52 02-11-2011 05:51 PM
Connecting a k100d to spotting scope? Petthefish Photographic Technique 8 07-24-2007 02:24 AM



All times are GMT -7. The time now is 01:01 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