Originally posted by Laurentiu Cristofor Yes, but it didn't get at this price because of demand. It got to have this price because Tamron has come out with an upgrade and decided to keep producing this lens as a budget option. Maybe they even changed something in the lens production to keep it cheaper.
Lens prices do fluctuate - but they don't fluctuate due to demand. Not from what I've seen. They fluctuate due to economic changes and they can change if the company strategy changes or if the production technology changes, but they won't change because a lens doesn't sell well or sells very well.
Yes, I'm sure. Follow those seller links. Adorama sells it for 964.95. B&H offers it at the same price. Look again at pricetrace's chart and you'll see that the low price hasn't changed for a while - it's always been 964.95. 1299.88 is just a bogus price to make 964.95 look good, but pricerate is not smart enough to figure that one out.
The FA 31 price did increase at least once - that was when the yen went up and all lens prices followed course. But it didn't increase because of demand.
Note I didn't say prices don't change - they just don't change as a result of demand.
The Rokinon has been available at $250 for more than a year. I don't need to check priceline - I've been watching Pentax lens prices for the past 3 years.
I looked at the links, and I think you're right in these instances about prices moving primarily in terms of exchange rates. The historical data on pricetrace is probably thrown off by MAP (minimum advertised pricing) requirements placed on auhtorized resellers, making their graphs as historical price indicators unreliable.
However, there are at least four lenses in the last few years which did experience price fluctuations due to supply/demand:
1) Pentax FA 50mm f/1.4
2) Pentax FA 35mm f/2
3) Sigma 24-60mm F2.8 EX DG
4) Tamron SP AF 24-135mm F/3.5-5.6 AD Aspherical
A few years ago, 1) and 2) were $200 and $300 respectively, for many months, from all major resellers. As they started to sell out, and demand went up, their prices rose everywhere, at different rates and different times, but they did ultimately rise everywhere.
There was also a lack of demand for 3) and 4) due to both of those companies coming out with more recent APS-C designs covering the same focal length, so 3) and 4) were cleared out for the very low prices of $200 (Nov 2008) and $158-$180 (Dec 2010) respectively at Amazon. I watched the Tamron very closely, and saw how as Amazon sold off the remaining stock they raised the price a little bit a few times as sales picked up, after attracting attention at $158.
These are the cases I know about for sure, and while they both demonstrate price increases and decreases due to market demand (or lack thereof), I do realize they are not extremely common, and these days, with Pentax doing better on average in the marketplace, are less likely to happen again.
However I wouldn't go so far as to say they don't/won't/can't happen.