55-300mm vs. 18-250mm vs. 70-300mm

[mutley]

Originally Posted by codiac2600

The only thing you're no considering is the 55-300 is an extremely sharp lens. It's just my opinion but I loved it and the build quality is great.

But did they completely eliminate CA? Oly did it in their new 70-300mm that is selling for about the same price.

Pentax need to take the elimination of CA seriously.

[opiedog]

Originally Posted by codiac2600

The onloy thing you're no considering is the 55-300 is an extremely sharp lens and overlap wise provides the least amount of overlap with the new kit lens. The 55-300 is designed to be sharper edge to edge for the K20D and I don't think any of the Tamron super zooms will compete with contrast and sharpness with this lens. It's just my opinion but I loved it and the build quality is great.

did you get a chance to take some sample shots with the 55-300?

i'm also seriously considering this to supplement my sigma 17-70.
price is ok at 350, MFD could have been better imho.

but if quality is good, i'll take it.

[ricardobeat]

Originally Posted by raz

you are talking about the 70-300 ? If yes, then is not in any way "awfully soft after 200mm", maybe you are talking about the sigma, but the tamron 70-300 has decent quality all over the range. It is not stellar but no soft either.
Here is a shot at 300mm f/5.6 no sharpening, no nothing

http://raz.ro/pentax/70-300/imgp6047.jpg

Please mind reading the quote. I was talking about the 28-300mm. The 70-300mm is sharper, but not great either and the purple fringing scared me away from buying it in less than 5 minutes (ugly 2px fringe on indoor tungsten lighting, come on!).

[ricardobeat]

Originally Posted by mutley

But did they completely eliminate CA? Oly did it in their new 70-300mm that is selling for about the same price.

Pentax need to take the elimination of CA seriously.

Man, stop doing that. The 4/3s system was designed to eliminate CA and other digital aberrations, you can't do the same on other optical systems. Few situations give ugly CA, and you can remove it in software.

[mutley]

Originally Posted by ricardobeat

The 4/3s system was designed to eliminate CA and other digital aberrations

The 4:3 system? What does that mean? Just because of the sensor size it doesn't get CA? Do you mean that if you stick Oly's 70-300mm lens on a Pentax body, it will have PF & CA all over the place?

That Oly lens has 3 full ED elements in it for $349. Does the Pentax 55-300? I mean Hoya owns them! It should have 4 ED elements!

If the 4:3 system has been designed to eliminate bad lens IQ, then Pentax should figure out a way to design APS-C system to do that.

I mean you tossed away a Tamron 70-300mm like it was a piece of disgusting junk because you got a bad sample with excess PF, and I love mine. The bit of PF I get can be processed out like you say, but for the $200 extra price of a camera brand lens, Pentax should design lenses that work with APS-C eliminating CA & PF.

[clawhammer]

I think another benefit with the 55-300 will be distortion. I've not experienced the 28-300 or 18-250, but I have toyed around with the Nikkor 18-200, and I'm really not all that happy with the distortion. If the 55-300 keeps distortion to a minimum and acheives sharp images above 200mm (a traditionally 'soft' spot for most consumer zoom lenses, granted that some are better than others but they're all a little soft) I would be willing to shell out ~400 for it.

[ricardobeat]

Originally Posted by mutley

The 4:3 system? What does that mean? Just because of the sensor size it doesn't get CA? Do you mean that if you stick Oly's 70-300mm lens on a Pentax body, it will have PF & CA all over the place?

That Oly lens has 3 full ED elements in it for $349. Does the Pentax 55-300? I mean Hoya owns them! It should have 4 ED elements!

If the 4:3 system has been designed to eliminate bad lens IQ, then Pentax should figure out a way to design APS-C system to do that.

I mean you tossed away a Tamron 70-300mm like it was a piece of disgusting junk because you got a bad sample with excess PF, and I love mine. The bit of PF I get can be processed out like you say, but for the $200 extra price of a camera brand lens, Pentax should design lenses that work with APS-C eliminating CA & PF.

The four thirds system was designed specifically for digital sensors. It's optical design allows the light to reach the sensor more evenly, at more straight angles. That eliminates all PF and lessens CAs, ghosting and flare, and also improves sharpness.

You can learn all about it here: Four Thirds

You can't "design APS-C system to do that". It's a completely different animal. It might only be doable if you don't mind having lenses that weigh 2kg each (you probably get a little bit of these benefits using 645 lenses on an APS-C body).

An Oly 70-300 won't cover half the frame of the pentax sensor.... but the exposed part will probably have NO fringing. The lenses are part of the equation too, it's all in the proportions.

I'm very confident that the 55-300mm will exhibit insignificant PF and CA compared to the Tamron. Yes, it was disgusting. I took a picture of a receipt over the counter to test the macro ability, and it had PF all around the blue lines on paper. It was even visible in the LCD at full size (not zoomed in). Small apertures didn't fix it. Bad copy or not, if a lens like that is allowed to be sold, I don't want any of them. I'm sure you can take wonderful pictures with it, as can be done with many other not-so-great lenses, and it's well worth the price. I just thought I could invest my money in something better, what I did later on with the Sigma 17-70 and 10-20.

The ED elements count is not criteria for image quality. It doesn't mean anything without knowing the design of the lens. They might be needed to compensate for light loss at another element :]

[AVANT]

After using my 50-200 DA for sometime, I find the sharpness a bit lacking (especially on the longer end). Fringing I can fix, lack of detail to begin with I cannot. IF the 55-300 is indeed much sharper while keeping with the pentax tradition of great color and contrast, then I'd upgrade if the bokeh is atleast equal. For my shoots, I've found 200mm to be enough, so it shouldn't be difficult for the 55-300 to be an improvement at 200mm (it'll already be slightly faster). I'm pretty excited for the lens actually.

[mutley]

Originally Posted by ricardobeat

The four thirds system was designed specifically for digital sensors. It's optical design allows the light to reach the sensor more evenly, at more straight angles.

Yes, I know the whole 4:3 story, being an OM user for years. Its one reason I chose to go with Pentax, and not Oly for digital.

You can give any marketing excuse you want for the amazing 4:3 system, but there are zooms and longer lenses for these APS-C cameras that don't exhibit CA. Therefore it is doable.

I just hope Pentax made sure to look closely in designing this lens for this one to exhibit this lack of CA or PF.

Especially since my sample of the Tamron is better than the one you saw, shows that partly it is build tolerances. Sigma, which you invested far more hundreds into after dismissing the $149 Tamron is known for producing many bad samples of otherwise good lenses.

Tight build quality tolerances like in Oly lenses, and corrected optical design is needed for the Pentax lineup as well. Especially since varying design of longer lenses yield different levels of CA with no CA examples in existence. And, they don't have to be 2kg.

[chetan.dighe]

I was just looking for a reply like this - 24x36NOW has hit the nail on the head. The further away you go from a zoom ratio of 1:3, image quality degrades, be it any brand, any range, any number of glass elements. The 28 from 28-300 is not as good as 28 from 28-80, and same goes to the tele end also - a 200 from 28-200 is not as good (read sharp / contrasty / whatever) as 200 from, say 70-210. I guess it is the complexity of optical design which gives this general 1:3 ratio as the upper limit of acceptable quality.

The wider aperture will also play its role in improving the image quality, which is another plus. But that is anyways the case.

[trumpyman]

Hi. Just want to say im more than happy with the 55-300mm.Heres a couple of shots at 300,i think it does a good job on the k20d
.Attachment 18423

Attachment 18424

Attachment 18425

Attachment 18426
1st shot 1/4000 ,ISO 500
2nd shot 1/4000 , ISO 1000
3rd shot 1/800 , ISO 500
4th shot 1/2500 ,ISO 1000
All shot at 300mm no PP as is from camera.I just wanted to show some samples at high speeds and high ISO. Hope its kool
Paul

[nulla]

I have this lens and find it quite good.



I like your shots... especially the last one.

I am into bird shooting as well.



Neil

[cupic]

Nicely done


cheers

[bart_hickman]

The key advantage of the 55-300 will be that it truly maintains 300mm F/L all the way down to the minimum focus distance whereas the 18-250 is closer to 100mm at the close end. So if you're shooting bugs and you want to keep your distance, the 55-300 will be significantly better (the 50-200 will be significantly better as well in this regard.)

I've also heard the AF speed of the 18-250 is slow. It might be (I don't know) that the 55-300 focuses faster if only because it probably has a simpler focuser which moves less glass when focusing.

Having fewer elements means the 55-300 might be a tad brighter and will have more dynamic range (less scattering between bright and dark areas of the image). And the 55-300 will have a hood that blocks flare better.

Robustness might be another thing. The 18-250 is very complex, perhaps over time it loses some IQ due to gradual misalignment of components. The simpler 55-300 design might be more robust over time.

Yet another consideration is bokah. Have no idea how they might compare here.

Of course none of this would explain anything about price--just considerations on choosing one or the other.

Bart

[Douglas_of_Sweden]

Originally Posted by offertonhatter

I would say that due to the reduced zoom range of the 55-300 over the 18-250, and possibly better optics, it commands a premium price. the 18-250 is in essence a tamron lens with pentax coatings, but the 55-300 seems to be a Pentax own model. It will be interesting to see how it compares with the Sigma 70-300 and the Sigma 70-300 APO lens which are very reasonably priced. It will be interesting.

The 55-300 is sure interesting and might be a way to extend upward in length, since I can't really motivate buying the much more expensive DA*300.

What about the FAJ 75-300? It is still for sale new here for a low price. What I heard it is better than the different FA/F 100-300 versions. How do you think it might compare to the DA55-300. The only possible advantage I can see, besides the price is that it is full frame, but without an aperture ring I'm not likely to use it on my film cameras and I might never go FF even if Pentax comes out with a FF camera, all depending on future prices and where the whole market goes. But forgetting that for the moment, just comparing FAJ 75-300 with DA55-300, what are the likely differences that would motivate me to go for the more expensive 55-300 (more than twice the price)? And are the Sigma/Tamron offerings so much better that I shouldn't think about the FAJ anyway?