jcolwell Online Upload & Sell: On
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A recent question, "Can you comment on your eBay strategy?", in this thread...
What is your most recent (alt) lens purchase?
https://www.fredmiranda.com/forum/topic/982966/204#12740294
...prompted me to write this rather long reply. I think it makes better sense to post it here, than in the Alt lens thread.
Lee Saxon wrote:
Can you comment on your eBay strategy? Do you have some kinds of alerts? Google searches? Non-US eBays? Even when I wait patiently I never find prices as low as your database. For example I've been checking that 125 periodically for over a year and I don't think I've ever seen it below $2000, regardless of condition (usually closer to that $2630, just by itself). Add $1200-$1400 for the 180, and $2630 for the trio is way below anything I've seen.
The basic methodology is described in the Lens$db documentation,
Lens$doc.pdf http://www.jcolwell.ca/photography/lens$db/Lens$doc-v28.pdf
I think the prices are realistic. For a few special Alt lenses like the CV 125/2.5 Macro, I track both Canon EF mount versions and other EOS-compatible versions, like Nikon-F, Pentax-K and Oly OM.
I just compared CV 125/2.5 Macro eBay sales data from the last two versions of Lens$db. For the CV 125 Macro in [E] to [E+] condition, there were no EF mount sales since I started tracking this lens. OTOH, there were a trickle of sales in other mounts. In Aug 2014, one sold for $1174 (US) and another in March 2014 for $1125. For non-EF mount CV 125 in [M-] to [LN] condition, one sold for $2150 in August 2014, and one for $2530 in March 2014. Here's the expression used in the current version of Lens$db for calculating the average sales price for this lens in [M-] to [LN] condition,
2328 =AVERAGE(2150,2530,2499,2680,2125,2250,1850,2599,2200,2400)
eBay prices for the EF mount CV 125/2.5 Macro in [M-] to [LN] condition are all over the price map. One sold in August 2014 for $3500, but the current average price is $2435. Here's the expression used in the current version of Lens$db for calculating the average sales price for this lens,
2434 =AVERAGE(3500,2350,2460,2225,2450,2000,2050)
I checked a bit further back into Lens$db versions and found that the sale of $2225 was in April 2013. The more rare lenses can have a long price legacy. I sometimes eliminiate outlier points, but only after it becomes obvious that they're not representative. For example, if I see two or three more CV 125 EF-mount [M-] sales at below $2500, I'll delete the $3500 entry in some future version of the database. The last two prices of $2000 and $2050 will probably be deleted from the next version of Lens$db, but for now, they kind of balance the most recent (crazy) sale of $3500. The only reason that I would have recorded this (crazy) sale was that it was the result of an active, multi-bidder auction, not some random Buy It Now sale (that are often quite expensive). I'll record a BIN sale if there hasn't been any action on that particular lens for over a year, but usually not.
If you have sufficient interest, you can do a more detailed comparison of Lens$db price histories yourself. All past versions of Lens$db back to v03 are online. You can just change the version numbers in current links to open the older versions. Excel versions switched from .xls in v20 to .xlsx for v21.
I started tracking eBay and online shop prices the for SMC Pentax Lenses and Other Stuff database (SPLOSdb) in 2008. I maintain the database for my own purposes; my current lens transaction count (buy+sell) is greater than 550. I figured that I'd share my database online, as a contribution to the large pool of internet resources related to photo gear. I note with some sadness that a lot of the best online resources and resource sites are disappearing over time.
Anyway, once a week or so, I do a review of all recent eBay used lens sales. Here's the stored shortcut that I use,
http://www.ebay.com/csc/Lenses-/3323/i.html?_ipg=200&LH_Price=100..100%2C000%40c&_sop=1&_trkparms=66%253A2%257C65%253A13%257C39%253A1&_catref=1&_dmd=1&_mPrRngCbx=1&LH_Complete=1&LH_Sold=1&rt=nc
I have the results page set up in 'list' format for 200 auctions at a time. I can usually go through a couple thousand listings before I fall off my chair.
When I'm getting ready to release a new update, I scan Lens$db to see if there are any 'important' lenses with no recent sales at all, and then I go into eBay to look for recent sales of those particular lenses.
I certainly don't get all of the sales, but I can guarantee that all of the eBay prices recorded in Lens$db were from actual sales. Of course, I'm not a complete idiot, and so I don't record obviously bogus sales (e.g. EF 400/2.8 L IS for $2300). I used to track auctions that appeared to be bogus (my bogus detector had about a 90% 'hit' rate), but I gave that up a few years ago. If I notice something bogus, I'll report it, but I don't seek them out anymore.
Cheers,
Jim
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