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03-09-2018, 09:52 AM   #1
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Cropping to a longer focal length?

I know this has been answered before, but this morning I simply canít figure out wording for a search.

With a k3ii would I be better off with something like a sigma 60-200 and cropping a 200mm image down to the area of my 55-300 or looking for a higher quality 200+ focal length lens? I wanna get into telephoto for abstract landscapes and compression but my budget is preventing me from buying 1200 dollar plus glass. My 55-300 just isnít thrilling me iq wise.

03-09-2018, 10:19 AM   #2
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Since you live in the US, I will recommend something I have done

rent equipment so you can do your own experimentation.

I have used LensRental.com from Tennesse

I know of Borrowlenses.com

there may be others

LensRental ships you the equipment and you ship it back

perhaps the 1.4 rear converter might be of help with your existing equipment ?

once you decide what you want, look for " experienced " equipment here at the Market Place or else where if you want to fit your purchase(s) into your budget

the members selling in the Market Place has treated me very well.

good luck

_____________________________________

FYI, I am very impressed with my " experienced " SMC Pentax-DA* 300mm F4 ED [IF] SDM

" Pentax-DA* 300mm F4 Review
Conclusion

The reason the DA* 300mm has so many loyal followers is that in use it is very smooth and feels like a high quality precision lens should. The mechanics and features of the lens are well thought out and make it a pleasure to use. The lens's optics deliver on its promise of exceptional sharpness. The DA* 300mm is a very well-constructed lens that handles remarkably. The lens is sharp and once it is stopped beyond 5.6 it is exceptionally sharp; it has great bokeh and no negligible chromatic aberration and distortion. "


Read more at: https://www.pentaxforums.com/reviews/pentax-da-300mm-f4/conclusion.html#ixzz59H4M587L

as well as my HD Pentax-DA 1.4x AW AF Rear Converter

" The Bottom Line

This rear converter is up there with the best in terms of optical quality. We can wholeheartedly recommend it in connection with quality lenses F4 or faster. The image quality with the converter beats upsampling a photo taken without it, so it's a no-brainer when you need that extra reach.

With F4 or faster lenses, autofocus works equally well with the converter as without it on modern Pentax DSLRs. Naturally, in low light the loss of one stop of light induced by the converter will affect autofocus speed. "


Read more at: https://www.pentaxforums.com/reviews/pentax-da-14x-aw-af-rear-converter/conc...#ixzz59H5sswOC

Last edited by aslyfox; 03-09-2018 at 10:44 AM.
03-09-2018, 10:56 AM - 1 Like   #3
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QuoteOriginally posted by Greenneck Quote
With a k3ii would I be better off with something like a sigma 60-200 and cropping a 200mm image down to the area of my 55-300 or looking for a higher quality 200+ focal length lens? My 55-300 just isnít thrilling me iq wise.
It really depends on the lenses. But in most circumstances if comparing zooms, using a longer focal length without cropping is going to give you better IQ than cropping with a short focal length.

The exception would be a comparison between a shorter telephoto prime like the Pentax SMCP-DA* 200mm f/2.8 ED (IF) SDM cropped vs. the 55-300mm zoomed in to 300mm.
03-09-2018, 03:11 PM   #4
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QuoteOriginally posted by Alex645 Quote
It really depends on the lenses. But in most circumstances if comparing zooms, using a longer focal length without cropping is going to give you better IQ than cropping with a short focal length.

The exception would be a comparison between a shorter telephoto prime like the Pentax SMCP-DA* 200mm f/2.8 ED (IF) SDM cropped vs. the 55-300mm zoomed in to 300mm.
I was thinking about replacing my 55-300 with a tam/sig 60-200 that way I have a fast high quality portrait length that maybe I can push for the occasional long focal shot or pick up a converter. Either that or save up and try to find a used bigma or similar super zoom

03-09-2018, 06:31 PM   #5
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QuoteOriginally posted by Greenneck Quote
I was thinking about replacing my 55-300 with a tam/sig 60-200 that way I have a fast high quality portrait length that maybe I can push for the occasional long focal shot or pick up a converter. Either that or save up and try to find a used bigma or similar super zoom
Yes, I understand. Without an actual test, it's all hypothesis, but I am fairly certain when it comes to cropping the 60-200 tam/sig to an equivalent 300mm FOV without cropping, it won't look equal...it will be slightly worse. If anyone actually has these two lenses and can post a side by side comparison with 24MP APS-C sensor, we'd know the real deal.
03-09-2018, 08:15 PM   #6
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I could also just pick up a Pentax 200mm F/4 SMC M K for about $80 and hope the image quality is better than my 55-300?
03-09-2018, 08:35 PM   #7
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QuoteOriginally posted by Alex645 Quote
Yes, I understand. Without an actual test, it's all hypothesis, but I am fairly certain when it comes to cropping the 60-200 tam/sig to an equivalent 300mm FOV without cropping, it won't look equal...it will be slightly worse. If anyone actually has these two lenses and can post a side by side comparison with 24MP APS-C sensor, we'd know the real deal.
I agree with Alex- the crop would nullify the IQ advantage of the 70-200mm f/2.8 lens compared with the DA 55-300mm, but not the f/2.8 advantage, if that is what you need. If you need the f/2.8 and also often use a shorter tele FL, the size, weight, and cost might be worth the effort. The M lens you mention at such low cost might be instructive at least. Even the TC has some quality compromise, and then you lose the f/2.8 advantage.

Since you would go that far to crop a 200mm image to get a 300mm image, it might be even better to go for a DFA 300mm f/4 prime lens (if you don't really need f/2.8), and keep using your DA 55-300mm at a shorter tele range, where its performance is better than at 300mm. Its performance at around 200mm is quite good, even compared with some 70-200mm f/2.8 lenses at that FL. And it can zoom down to 55mm instead of 70mm.
03-09-2018, 10:44 PM - 2 Likes   #8
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The 55-300 is a fine lens. It's no match to my DA*300, but it gets the job done.
Which version is yours? Mine is the HD, non-PLM.









03-10-2018, 12:42 AM   #9
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QuoteOriginally posted by Greenneck Quote
My 55-300 just isnít thrilling me iq wise.
QuoteOriginally posted by Sandy Hancock Quote
The 55-300 is a fine lens. It's no match to my DA*300, but it gets the job done.
Which version is yours? Mine is the HD, non-PLM.
Love those examples Sandy. Especially the hay rolls.

Greenneck, Can you post a couple examples with the meta data where your 55-300mm wasnʻt thrilling you IQ wise?
03-10-2018, 03:32 PM   #10
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QuoteOriginally posted by Alex645 Quote
Love those examples Sandy. Especially the hay rolls.

Greenneck, Can you post a couple examples with the meta data where your 55-300mm wasnʻt thrilling you IQ wise?
300 test | Flickr That's a link to a album I put together They should all be unedited. I've also posted about it in a previous thread. My main issue is how the lens handles highlights especially around edges. One of my tests, with a cement ball showed if I could stop way down to f13 that edge was gone but that's just not very practical most of the time.

I can actually see that same edge in Sandy's photo of the car. My lens is also the HD none plm model

Last edited by Greenneck; 03-10-2018 at 03:35 PM. Reason: details
03-10-2018, 04:04 PM   #11
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QuoteOriginally posted by Greenneck Quote
300 test | Flickr That's a link to a album I put together They should all be unedited. I've also posted about it in a previous thread. My main issue is how the lens handles highlights especially around edges.
Justin,
Thanks for the link. The green/blue fringing on the edge is chromatic aberration. I assume these were shot RAW? All lenses under certain circumstances will have more or less CA and one way to compare actual tests with one sample test lens and, for example, the K3, is to use the dxomark.com data base:

Camera Lens Database - DxOMark

As youʻll see, primes rule the IQ from most technical evaluations before you begin to see zooms.

With RAW files, youʻll just have to find your favorite photo editing software to reduce or eliminate it or else pay the piper for a lens with very little CA. Have you tried shooting high quality jpegs to see how well the in-camera processor eliminates CA?

Also, have you tried AF fine adjustment? Itʻs trickier with a zoom, but if you find youʻre often shooting at 300mm of subjects at a certain distance, you can try adjusting the AF to correct for slight back or front focusing. If youʻre uncertain for distances, Iʻd first check infinity and then maybe something as close as your shot of the bees.
03-10-2018, 05:25 PM   #12
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QuoteOriginally posted by Alex645 Quote
Love those examples Sandy. Especially the hay rolls.

Greenneck, Can you post a couple examples with the meta data where your 55-300mm wasnʻt thrilling you IQ wise?
Right, Sandy- I meant the DA* 300mm f/4 prime
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