Originally posted by Dan Rentea Having a:
- 400mm f2.8 lens
- 500mm f4 lens
- 100-400mm f4 lens (the one with 1.4x TC build in)
- or a 600mm f4 lens
it means that you don't need a Sigma/Tamron 150-600mm lens.
We're talking about budget friendly lenses and the lenses listed above are top class lenses, the most cheaper lens costing 9.000$.
Neither:
- Pentax DA* 300mm F4
- Pentax 150-450mm
- Sigma/Tamron 150-600mm
- Canon 100-400mm f4.5-5.6L
- Nikon 200-500mm f5.6
are not in the same class as the lenses listed above.
The fact that they are not listed in the same class, does not make them all equal. The Sigma Tamron 150-600 lenses are ƒ6.3, even at 400mm. The puts them a class below my A-400 ƒ5.6, and below my Sigma 70-300 which is also ƒ5.6.
I'd love to see image comparisons between the Canon 100-400, Nikon 200-500 5.6 and DA 150-450 as they are all pretty much the same class of lens. And in my experience there is a severe difference in AF capability between ƒ5.6 and ƒ6.3 when using TC's so, yes it does make a difference. At that point you have to start looking at the IQ the lens produces and by all accounts the Pentax 150-450 is very good.
But, simple rule of thumb, faster means more weight, traded for better low light performance, and the ability to accept and make use of a TC.
With all due respect, a 6.3 lens is not in the same class as a 5.6 lens, which is not the same as an F4 lens.
However look at a different way at 200mm, these lenses
- Sigma/Tamron 150-600mm
- Canon 100-400mm f4.5-5.6L
- Nikon 200-500mm f5.6
Are not in the same class as the DA*200 ƒ2.8
At 300mm these lenses
- Sigma/Tamron 150-600mm
- Canon 100-400mm f4.5-5.6L
- Nikon 200-500mm f5.6
Are not in the same class as Pentax DA*300 ƒ4. which with 1.4 TC gives you 420 ƒ5.6 or with the 1.7x gives you 510 ƒ6.3.
And no matter which way you look at it, ƒ6,3 is bottom of the heap.
Honestly ask yourself... can you buy a worse choice to get yourself to 600 than a Sigma/Tamron 150-600? All it has going for it is it's relative price.
So really what you're doing here is building up your beloved 150-600 by throwing it into a pile with a bunch off lenses, that are a class above. and hoping no one will notice. And we haven't even discussed the Pentax 60-250 ƒ4, which in it's range will pretty much outclass any of those lenses. Some of the lens designers on the forum have stuck with Pentax, just to get this lens. So yes, some companies make some lenses Pentaxians might like, and Pentax makes some lenses that people from other camera companies might like, but, it's not just ƒ4 long lenses that leave 150-600 type lenses in the dust, it's practically everything Pentax makes. No matter what you do, ƒ6.3 is ƒ6.3. There's no excaping it.
Anyone who focuses on one type of lens and then says Pentax is at a disadvantage because they don't have it is myopic. (look it up in the dictionary.) By focussing on one particular lens, you make a case for the "Pentax disadvantage." The Pentax advantage is small portable high quality primes and DA* lineup that provides great quality and functionality in very portable packages, with great build quality and tank like construction. I could say, well Canon and Nikon users really don't have a 77 ltd. type lens available to them. They should all be switching to Pentax. Or there's nothing as good as the Pentax 60-250 in the Canikon world, with prime quality throughout it's range at that size and weight.
People can say stupid stuff like that, but for the most part they don't. So why do we get ignorant Canon users on the forum explaining why they love their Canons, with their crappy Dynamic Range and low resolution. It's simple dude. We don't value what you value. All your "why I use Canon instead of Pentax" nonsense won't change that. You've settled into a set of compromises we won't make. So while I'm glad you're happy with them, they wouldn't make me happy. Get used to it.