[Tigs]

I currently own a da 55-300 f5.8 and am considering stepping up

I'm looking for an option that
- provides sharper results, especially at appertures faster than f8
- has better af for acquiring focus on fast moving subjects
- has longer reach without compromising image quality

Other notes:
- I dont mind fixed focal length lenses

Would the sigma 500mm f4.5 be a good option? What lenses should I consider

[boriscleto]

The Sigma is an excellent lens, but you can get the D FA 150-450 for less than half the price and it meets your requirements.

If Ricoh made a D FA 2x TC the D FA 70-200 would be an option, but I don't see that happening anytime soon.

[aslyfox]

I am certainly not an expert but I really like my D FA 150 - 450 mm

have you looked at these threads, perhaps those might help you to make your decision

The 300mm plus lens Club discuss your long lenses. - PentaxForums.com

Post your HD PENTAX-D FA 150-450mm F4.5-5.6 ED DC AW pictures! - PentaxForums.com

HD Pentax-D FA 150-450mm F4.5-5.6 Review - Introduction | PentaxForums.com Reviews

[Scorpio71GR]

The Sigma 500 4.5 is certainly when of the best options. It is much more compact than the DA 560. Many people do just fine with the DA*300 and 1.4 HD TC. That gives you 420mm and f5.6, still not bad. The Sigma 500 is screwdrive and that is the only option in K mount as far as I know. The DFA 150-450 is another option and probably the way I would go. Although you may want to consider if you want to handle a 4lb lens. If you really want to go big there are the F and FA 600 f4 lenses.

[Adam]

The 55-300mm PLM has much faster AF if you want a quick fix for that. Otherwise my recommendation would be the 150-450mm.

[boriscleto]

The DFA 150-450 is another option and probably the way I would go. Although you may want to consider if you want to handle a 4lb lens..

The Sigma is 6.93 lbs...

[Scorpio71GR]

The Sigma is 6.93 lbs...

Yeah I know that thing is a beast. Which is why I will never have one. I have enough trouble with my 50-500.

[btnapa]

Otherwise my recommendation would be the 150-450mm

+1 on Adam's and other people's recommendation. Although I do not have the lens, I have tried it at photo shows on more than one occasion. It is a fantastic lens and on a crop sensor you are approaching 700mm... that is quite a reach! Although on the heavy side, it is not that bad and the focus was pretty fast on my K3.

[aslyfox]

The Sigma is 6.93 lbs...

as Scorpio71GR said

D FA 150 - 450

Weight
2000 g (70.5 oz.) w/o hood or 4.40625 pounds
2130 g (75.1 oz.) w/ hood
2325 g (82.0 oz.) w/ hood & tripod mount

[KiloHotelphoto]

I would recommend getting the longest fastest prime you can afford, with zooms you will always be using the long end for wildlife.

I started out with the Sigma 150-500 and after a year 90% of my shots were at 400-500 so I upgraded to the 560 and the image quality was such a improvement. If you can afford the Sigma 500 4.5 or a Pentax 560 5.6 that's what I'd get.

[Cthulhugan]

The DA* 60-250 with the DA 1.4x teleconverter gets you out to 350, with better IQ than the 55-300.

[UncleVanya]

The DA* 60-250 with the DA 1.4x teleconverter gets you out to 350, with better IQ than the 55-300.

While this is true it is not all that much more magnification even at infinity. The quality is higher but it is subtle. The bigger problem with this kit is that the closer distance use of the 60-250 even with the converter leaves a lot to be desired in terms of magnification due to focus breathing.

A few users like to use the F 1.7 TC with the DA* 200 and even stack the DA 1.4x and the F 1.7x at times. The results are not bad.
Other options would be the DA or FA or F 300 and the DA 1.4x.

Overall it depends a lot on what you will be shooting and if zooming is required.

[biz-engineer]

On crop 400mm should be fine. DA*300+TC or DFA150-450. DA*300 F4 + TC have the best IQ, light weight, downside of DA*300+TC is the SDM motor of the lens and if the TC is not full frame and you want to upgrade to full frame in the future. DFA150-450 works well, solid AF drive and for FF image circle.

[angerdan]

I'm looking for an option that
- provides sharper results, especially at appertures faster than f8
- has better af for acquiring focus on fast moving subjects
- has longer reach without compromising image quality
- I dont mind fixed focal length lenses
What lenses should I consider

• Sigma 100-300mm 4.0 with 1.4x TC
• Sigma 300mm 2.8 with 1.4x TC (easier to find than FA* 300mm 2.8)
• FA* 300mm 2.8 with 1.4x TC (has AF-limiter)
• FA* 400mm 5.6 (cheap)
• DA 560mm 5.6 DC AW (weatherproof)

On crop 400mm should be fine. DA*300+TC or DFA150-450. DA*300 F4 + TC have the best IQ, light weight, downside of DA*300+TC is the SDM motor of the lens and if the TC is not full frame and you want to upgrade to full frame in the future. DFA150-450 works well, solid AF drive and for FF image circle.

It's possible to use the Tokina/Tamron TK, which is FF and has Pz-AF pins.

[grispie]

I would recommend getting the longest fastest prime you can afford, with zooms you will always be using the long end for wildlife.

Based on my recent safari in botswana and a walk around a nearby reed marsh with my 55 300, 2 questions/comments:

1. "wildlife" needs to be defined
2. Is 450 really long enough for wild birds? With the 55-300 i could only make images in that reed area with the birds appearing too small (and they were no small birds, but rather shy herons..)

just a thought