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12-04-2017, 07:20 AM   #1
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APS-C in 70- 200/ 2.8 range

I am looking for a two lens kit for my K3. I have the Tamron 17-50/ 2.8 and absolutely love it. I am now looking for that next step in reach to close out my kit. Something in that range but I am coming up empty. I considered the 50-135 but any samples I see are kind of soft in the 2.8 to 5.6 range. When I shoot cars, I am in need of a more open aperture most of the time to get the isolation I am looking for.

I have a bunch of primes but they are A or F series and are used on my film bodies, which I shoot at the same time as the K3.

12-04-2017, 07:57 AM   #2
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I'd consider the Tamron 70-200 if cost is an issue or the DFA 70-200 gif it isn't.

But, the 50-135 is not soft edge or border in most configurations. You can go to a bigger lens, but getting better images is going to depend on technique. If the 50-135 is what you think you need go for it. It's a great lens. Only the best ZIess lenses are sharpest at ƒ2.8. Expect to pay between $2000 and $5000 for a prime if that's what you really want.



Look at this Zeiss at ƒ4. You pay a lot more for a bit of extra sharpness/


Zeiss Milvus 100mm f/2M ZE Lens for Canon EF - $1,843.00

Sorry, the two Zeiss lenses above ar not the same but, I couldn't get a lens chart for the Milvus. But it just gives you some idea of what you re looking at if you really want razor sharp edge to edge ƒ2.8. I would argue you can make do with a 50-135 and get excellent results. Your opinion of the 50-135 is not shared by any owners I know of. That being said, the 55-300 PLM might be worth a look. For shooting moving objects it's probably the fastest focussing lens on Pentax, but it doesn't go anywhere near ƒ 2.8.

Last edited by normhead; 12-04-2017 at 09:57 AM.
12-04-2017, 08:19 AM   #3
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I can definitely recommend the Tamron 70-200 f/2.8. Sure, it is screw drive, so not silent, but it is sharp, and on APSC you will be using the center where it is sharpest.
12-04-2017, 08:27 AM   #4
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QuoteOriginally posted by VoiceOfReason Quote
I can definitely recommend the Tamron 70-200 f/2.8. Sure, it is screw drive, so not silent, but it is sharp, and on APSC you will be using the center where it is sharpest.
You do have to watch for bad copies of that lens though, more than most lenses. Where ever you buy it if you do, be prepared to exchange it if your first copy isn't up to scratch. Everyone with a good copy seems to be just thrilled with it.

12-04-2017, 08:56 AM   #5
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50-135 isn't soft wide open. At least that's not my experience. Can you post examples? Sigma 50-150 is only available used but offers an alternative.
12-04-2017, 09:01 AM   #6
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QuoteOriginally posted by VoiceOfReason Quote
I can definitely recommend the Tamron 70-200 f/2.8. Sure, it is screw drive, so not silent, but it is sharp, and on APSC you will be using the center where it is sharpest.
Yeah, I do not care about silence. Is that a full frame lens? I am looking for an APS-C specific lens. The DFA is a great lens but it is very expensive and full frame so the FoV is going to be changed.
12-04-2017, 09:18 AM - 1 Like   #7
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QuoteOriginally posted by derelict Quote
I am looking for an APS-C specific lens. The DFA is a great lens but it is very expensive and full frame so the FoV is going to be changed.
It is expensive and FF , but it will still be a 70-200mm lens on your K3. Fov will be no different.
12-04-2017, 09:47 AM   #8
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My dad after a lifetime of photography still gets this confused. It is easy to get mixed up. But as said above the lens isn't what changed the view. Put an apsc at 70mm and a full frame lens at 70mm on the same k3 and they both should look the same. Put the full frame on a k-1 and it will look wider since part of the image width and height wasn't able to be seen by the smaller sensor of the k-3, but the central portion of the frame won't appear much different from the k-3.

12-04-2017, 10:38 AM   #9
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QuoteOriginally posted by pschlute Quote
It is expensive and FF , but it will still be a 70-200mm lens on your K3. Fov will be no different.
FoV will not be different? Do not think that is true. One of my favorite film lenses is my A135/ 2.8. A shot with that on my MX and then a shot with that on my K3 will yield different results. The FoV is different. If I put a lens designed for 35mm and a range of 70-200 on an APSC sensor, it is not equivalent to a lens designed for the 70-200 range APSC lens.
12-04-2017, 10:57 AM   #10
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QuoteOriginally posted by derelict Quote
FoV will not be different? Do not think that is true. One of my favorite film lenses is my A135/ 2.8. A shot with that on my MX and then a shot with that on my K3 will yield different results.
This is true

QuoteOriginally posted by derelict Quote
The FoV is different. If I put a lens designed for 35mm and a range of 70-200 on an APSC sensor, it is not equivalent to a lens designed for the 70-200 range APSC lens.
If you were to use the DA*50-135 at 70mm on your K-3, the field of view would look the same as the D FA 70-200 at 70mm on your K-3, both of which would match the field of view given by the DA 70mm Limited.
12-04-2017, 11:01 AM   #11
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QuoteOriginally posted by derelict Quote
FoV will not be different? Do not think that is true. One of my favorite film lenses is my A135/ 2.8. A shot with that on my MX and then a shot with that on my K3 will yield different results. The FoV is different. If I put a lens designed for 35mm and a range of 70-200 on an APSC sensor, it is not equivalent to a lens designed for the 70-200 range APSC lens.
The MX is 35mm film, and that's what full frame matches for size, so yes, field of view would change going from the MX to the K3. The K3 is APS-C - smaller sensor, so smaller section of the image circle is captured. A full frame lens has a bigger image circle, so the image can cover a larger area. Crop is a subset, but a 135mm lens is always a 135mm lens. How much of the image circle you're looking at is what's being reflected between APS-C and full frame. Any full frame lens will work on APS-C since the full frame area is larger than APS-C. However, since a lens designed for APS-C only has to produce an image for a smaller area, they often will show vignetting on full frame, if the image even goes to the edges of the full frame, and that will just get down to the luck of the design. And a final thought is if you have a lens that is designed for full frame, it is apt to have great sharpness in the corners of the APS-C area because it's not at the edges of the image circle it has to cover as a full frame lens. All said though, any lens of X focal length, whether designed for full frame or APS-C, will have the same field of view when mounted on an APS-C body. Put that same focal length lens on a full frame camera, and the field of view will be greater because you're seeing more of the image circle (assuming the lens is capable of producing a full frame image circle).
12-04-2017, 11:05 AM   #12
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All of the above is why I am looking for an APS-C specific lens, not just using a DFA lens on the K3. Center will be the same but I do not center a lot of my subjects.

So, the Sigma 50-150 and the Tamron 70-200 are the best bets?
12-04-2017, 12:04 PM   #13
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QuoteOriginally posted by derelict Quote
FoV will not be different? Do not think that is true. One of my favorite film lenses is my A135/ 2.8. A shot with that on my MX and then a shot with that on my K3 will yield different results. The FoV is different. If I put a lens designed for 35mm and a range of 70-200 on an APSC sensor, it is not equivalent to a lens designed for the 70-200 range APSC lens.
That is actually incorrect. 70mm is 70mm whether the lens is designed for APSC or FF. The biggest difference is that a FF lens will be bigger because a FF has a wider and taller sensor.

Here's something for you to do to prove this to yourself. Take your 135mm lens and go shoot an object across a field with it. Now, go grab a lens that is designed for APSC, but 135mm falls within the range of it if a zoom, set it at 135mm, and take a pic of the same thing. Your images will have exactly the same FoV.

A FF camera will always have a wider FoV than an APSC camera at the same MM, just as an APSC camera will always have a wider FoV than an M43 camera with the same MM lens on it. 70mm is 70 mm is 70mm, and the same is true for 200mm, 50mm, 135mm, 235mm, or any other you care to put up.
12-04-2017, 12:19 PM   #14
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QuoteOriginally posted by VoiceOfReason Quote
That is actually incorrect. 70mm is 70mm whether the lens is designed for APSC or FF. The biggest difference is that a FF lens will be bigger because a FF has a wider and taller sensor.

Here's something for you to do to prove this to yourself. Take your 135mm lens and go shoot an object across a field with it. Now, go grab a lens that is designed for APSC, but 135mm falls within the range of it if a zoom, set it at 135mm, and take a pic of the same thing. Your images will have exactly the same FoV.

A FF camera will always have a wider FoV than an APSC camera at the same MM, just as an APSC camera will always have a wider FoV than an M43 camera with the same MM lens on it. 70mm is 70 mm is 70mm, and the same is true for 200mm, 50mm, 135mm, 235mm, or any other you care to put up.
But an indicated 70mm on a K1 DFA lens when put on a K3 will not yield 70mm but a higher, narrower focal length. Hence, my looking for an APSC specific lens.
12-04-2017, 12:37 PM   #15
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When a lens is listed as APSC or full frame all thats referring to is the image circle. An 100mm APSC lens is going to give you the same FOV as a 100mm FF lens if used on the same body. Since your shooting with an APSC body it makes no difference if you use an APSC lens or a FF lens. Focal length is constant no matter what sensor format you're using. Focal length and FOV are related but they are not the same thing.
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