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02-14-2013, 08:08 AM   #31
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QuoteOriginally posted by stormtech Quote
No apologies necessary! I myself get easily confused when I start throwing all these numbers and crop factors around. Just wanted to be sure that you are applying the 5.5x to the actual focal length of the lenses you are looking at.

I'm just getting started with the Q - only got my first Q body in December so I haven't had the chance to do any real testing outside like I want to. I've been testing different lenses from inside through our big glass window to get a feel of the different focal lengths. One of my main goals is to be able to shoot at the opposite bank of the river at my house where the 300mm will work well (1650mm eq). But at that focal length, objects are a little difficult to acquire in the LCD and need to have a fairly static subject plus use a remote or 2 second timer and on a sturdy tripod. To make all those things mentioned a little easier, I just bought an M 150 3.5 lens which will be 825mm eq. I think this is a nice compromise for a nice long focal length and to be able to hand hold if needed and be usable for ducks on the water that are moving/floating slowly. So far just with a little testing today I think this focal length is going to be just right for me.
Thanks again for the reply, Stan.
Yes, I have taken the 5.5x factor when looking at lenses.

Now that I am reading this post of yours, it makes me think that the DA*300/4 on the Q for "birding" might not be such a great idea after all, (for me, that is) ; of course, it has great reach but it also means that it becomes difficult to acquire the "target", especially if it is moving.
So, what I am reading is that a 135-150 lens (with good IQ) would be preferable for the type of photography I do most of the time.
The resulting "focal length" would be just fine with me too ! and probably easier to hand hold in trickery trails and such places.

I will be doing a little searching for "the best" 135mm-ish lens out there, if there is such a thing, for the Q, and as long as it doesn't cost an arm and a leg!
(I wonder if my Vivitar 135/2.8 Close Focusing would fit this criteria ? But it's a totally manual-everything lens ... just throwing ideas around.)

Going back to my original post regarding a 500mm eq. .... let's just say that it is an improvement over 300mm but if one can get 800-ish with good IQ: great!

So, I am looking forward to get this adapter from Henry's ... a few days, probably early next week.

Cheers!

JP

02-14-2013, 08:22 AM   #32
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Sounds like you are on the right track JP.

And with the manual lenses, with the Q it really doesn't matter. If seems that using lenses on the Q, they all have their certain sweet spot as far as aperture. Let's just say that f5.6 is that sweet spot for your Vivitar lens. Then you just set the aperture at f5.6, and go shooting. From there it is just manual focus. Maybe I am wrong here, but in my experience, when you put the adapter on the Q with any lens, it turns the Q into aperture priority mode automatically. I set the lens at f5.6, set my ISO range (usually 125-800 for me), and the Q will set the proper shutter speed itself. So once I have those parameters set, it's just a matter of manually focusing, and shoot.

Once you have your adapter in hand, try a couple of the lenses you have. You will need to try that Vivitar lens at different apertures to find its sweet spot, but you might find that lens will suit you quite well. Just one thing - don't expect any of the lenses on the Q to compete with the DA*300 on the K-5 - it just won't do it. But, you can come very close with the proper settings on other lenses. And just look at the cost - in that pic I posted above, the Q cost me $90, the adapter $15, and the lens $55. So there I am shooting at 825mm for $160. If the images aren't quite what I get with the DA*300 and K-5, for that price, it is OK.
02-14-2013, 08:30 AM   #33
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QuoteOriginally posted by stormtech Quote
No apologies necessary! I myself get easily confused when I start throwing all these numbers and crop factors around. Just wanted to be sure that you are applying the 5.5x to the actual focal length of the lenses you are looking at.

I'm just getting started with the Q - only got my first Q body in December so I haven't had the chance to do any real testing outside like I want to. I've been testing different lenses from inside through our big glass window to get a feel of the different focal lengths. One of my main goals is to be able to shoot at the opposite bank of the river at my house where the 300mm will work well (1650mm eq). But at that focal length, objects are a little difficult to acquire in the LCD and need to have a fairly static subject plus use a remote or 2 second timer and on a sturdy tripod. To make all those things mentioned a little easier, I just bought an M 150 3.5 lens which will be 825mm eq. I think this is a nice compromise for a nice long focal length and to be able to hand hold if needed and be usable for ducks on the water that are moving/floating slowly. So far just with a little testing today I think this focal length is going to be just right for me.
I think this picture with the 150/K adapter/Q/Hoodman style loup is the best argument for a version of the Q series with an integrated/accessory EVF.
02-14-2013, 08:48 AM   #34
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QuoteOriginally posted by jpzk Quote
it has great reach but it also means that it becomes difficult to acquire the "target",
This is where the Red Dot scope comes in.

02-14-2013, 09:20 AM   #35
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Inexpensive fun

I haven't done the math yet, but I would own (all Pentax OEM, of course)
  • $125 = a Deal-Priced Q
  • $249 = a Pentax Q for K adapter
  • $46 = DA8300 Pentax Tripod Foot
  • $75 = Pentax Red-Dot Finder with hot shoe converter
  • $80 = Hoodman-style LCD loupe
  • $575 = Total "Reach" investment
I assume we all have a good tripod and ballhead setup.

That's actually pretty inexpensive for the fun quotient of long shooting, especially if the real, final absolute possible IQ doesn't need to be image-collector quality (my sister-in-law would never tolerate what she can pull from tis rig).

For a couple years I had a Pentax M42 version 500/4.5 that cost more than this total setup and it was a beast, impossible for me to stabilze and focus - and its sheer size in the case was a constant reminder to my accountant (she sleeps in the same bed) that I have some money tied up in this hobby. That lens is now on the "I had it, I tried it, I sold it and I'm glad I had the chance" list (IOW crossed off the bucket list).

Of course none of that even acknowledges what we can do with Q lenses, which almosts eems to be icing.
02-14-2013, 09:26 AM   #36
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QuoteOriginally posted by stormtech Quote
So then which is it? Do you multiply the focal length of the lens by 3 or 5.5? I was just going by the norm that I've seen here on the forum of 5.5x.
Depends what you want to compare. Field of view for a given focal length, use the crop factor (around 3.7 compared to Pentax APS-C, around 5.5 compared to full 135 format).

QuoteOriginally posted by panoguy Quote
I think what he means is "3x advantage over an APS-C camera like the K-5."
No, over any camera with the pixel density of the K-5, which would also include the Nikon D800.

QuoteOriginally posted by crewl1 Quote
I interpret this to mean that there are three times more pixels in the area of the Q sensor vs. the same size area of an APS-C sensor , presumable a 16MP from a K-5?
Right, although the 3x is actually linear (9x the pixels per area).

The extra reach of the Q is not because the sensor is small. You could always shoot on the K-5 and crop the image to the same field of view. That's why crop factor is more or less irrelevant to the question of reach. What the Q gives is extra pixels, allowing you to enlarge the image more. It has roughly 3x the (linear) pixel density, but I consider the practical advantage less than this, because of the extra noise of the Q sensor, and also because of the difficulty of focusing accurately enough (and keeping the camera steady enough) to take full advantage of the extra resolution.

QuoteOriginally posted by jpzk Quote
So, what I am reading is that a 135-150 lens (with good IQ) would be preferable for the type of photography I do most of the time.
A 150 would give you a slight increase in effective reach over the 300 on the K-5. Weigh that against the disadvantages in handling. It would have to be an exceptionally good 150 to match the IQ of the 300.
02-14-2013, 09:57 AM   #37
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QuoteOriginally posted by crewl1 Quote
As you test out the lenses please add a review to the reference thread to help others in the same spot.
I think there is a review of an 85 1.4 there you can check.
First page has the index.
It will be some time before I get to testing (won't have the camera until next week - and that will be a very busy time for work). I see the Samyang 85 review, but it really only is some close up shots of a black flash box with white lettering. Hard to know how it will do in a more practical situation. But, yes, I plan on some thorough tests that are replicated on about five lenses, and then posted. My preference is to work from RAW, but will set up a standard LR process in terms of sharpening and NR.
02-14-2013, 10:25 AM   #38
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It would be a good idea to note that the Q is diffraction limited at f/2.8. You may not get the resolution you expect with slower telephoto lenses.

--DragonLord

02-14-2013, 10:35 AM   #39
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QuoteOriginally posted by DragonLord Quote
It would be a good idea to note that the Q is diffraction limited at f/2.8. You may not get the resolution you expect with slower telephoto lenses.

--DragonLord
This is true, but in practice we are finding that the greatest determination of image quality on the Q for adapted lenses is the sweet spot of the lens aperture wise, and it's ability to deliver center sharpness without aberrations.
In my testing most lenses that do well are coming in around f5.6 on the Q.
This is true for the DA*300, DFA100WR, Sigma 70-200 HSMII.

Lenses that are already at a disadvantage due to a sweet spots in the f8-f11 range will have diffraction issues on the Q for distant objects.
This may not be that much of a problem for closer, frame filling shots.
02-14-2013, 10:07 PM   #40
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Super fast lenses not necessary?

It is easy to put too much stock into the diffusion problem on a tiny sensor. Everyone assumed that the 02 zoom was going to be terrible because it just wasn't fast enough. Well, the testing appears to show that the zoom pretty much matches resolution of the 01 at any f-stop (but you do lose the isolation of the faster lens). Of course, you lose the miniature aspect with the zoom, but the idea of a presumed IQ gap (ala Ltd. vs. kit zoom) clearly isn't there.

I will be interested to see a comparison of the Q 15-45, the Kda 16-45, and the Kda 16-50. I'm just guessing that in IQ they will finish in that order - and it won't be particularly close when comparing them. The first was designed for the sensor; the second is a superb optic (disclosure - I have the lens); and the last one, well, is very well built (except the early SDM disasters) and won't fog up in a downpour.
02-15-2013, 05:49 AM   #41
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QuoteOriginally posted by ScooterMaxi Jim Quote
It is easy to put too much stock into the diffusion problem on a tiny sensor.
It's easy to put too much into the <diffraction> problem on any sensor. The K-5 is diffraction limited at, what, f/5.6? But on the subject of the reach of the Q it is very much a concern, at least for those of us photographing birds -- feather detail is exactly the kind of detail where you can most easily notice diffraction, so you really do want a lens that performs well by f/5.6.
02-15-2013, 09:54 AM   #42
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With all of that being said and "almost" done about which lens(es) to use to reach out, I was thinking that it would be a great idea to have a "Sticky" thread on actually setting up the Q/adapter with detailed instructions, preferably visual such as pictures and videos.
Maybe there is one but if so, where is it?
This would include mounting and setting up the adapter/camera stettings for different lenses whether they'would be manual or AF-capable ... etc.

Why? Because I am sure that there are more people like me: not good at technicalities/hardware operations.

Cheers!

JP

Note: adapter not yet in .... I contacted the seller and it is supposed to be "in a few days".
02-15-2013, 10:05 AM   #43
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QuoteOriginally posted by jpzk Quote
With all of that being said and "almost" done about which lens(es) to use to reach out, I was thinking that it would be a great idea to have a "Sticky" thread on actually setting up the Q/adapter with detailed instructions, preferably visual such as pictures and videos.
Maybe there is one but if so, where is it?
This would include mounting and setting up the adapter/camera stettings for different lenses whether they'would be manual or AF-capable ... etc.

Why? Because I am sure that there are more people like me: not good at technicalities/hardware operations.

Cheers!

JP

Note: adapter not yet in .... I contacted the seller and it is supposed to be "in a few days".
See Using the K-Mount Adapter for Pentax Q - Pentax Camera News & Rumors - PentaxForums.com
02-15-2013, 10:19 AM   #44
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As usual ... total embarassment !

And, thanks for the link!

JP

Edit: this is a great little "tutorial" and it is also mentioned that more info will be available in the future.
Expect me to be asking more questions sometimes next week though.

Last edited by jpzk; 02-15-2013 at 12:00 PM.
02-15-2013, 11:46 AM   #45
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Once again - our resident Q Mentor (Qentor?) Larry comes to the resQ !!
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