Originally posted by creampuff If the responses on Pentaxforums/DPreview is but a sampling of the number of Pentax SDM lenses users globally, the fact remains that this tally seems like a very small number of respondents, considering the thousands of SDM lenses that Pentax has sold worldwide...
Like here, DPR may have 16000 members, but only a few hundred are actually posting. 60 some people out of a few hundred? 60 people is 1% of 6000, 60 is 10% of 600.
Or look at it as lenses, 75 is 1% of 7500, 75 is 10% of 750. Do you think there are 7500 SDM lenses owned by the people that post at DPR? Do you think there are 750 SDM lenses owned by the people that post at DPR?
Although I used 1%, I personally think a 0.1% is the acceptable number, 75 is 0.1% of 75000. Do you think the are 75,000 SDM lenses owned by the posters at DPR? 60 is 0.1% of 60,000. Do you think there are 60,000 people posting to the Pentax forum at DPR?
Originally posted by creampuff We got one of the biggest Pentax users in one place where I am and the number of SDM failures that we roughly know of from users who we know in person, and from our local Pentax repair technician, is extremely low.
I'll let everyone draw their own conclusions whether this problem has been overblown or not.
From the photos that have been posted of the Singapore group, it looks like you have about 50 people. How many SDM lenses are owned?
1% of 100 is 1, 10% of 100 is 10.
1% of 50 is 0.5, 10% of 50 is 5.
1% of 25 is 0.25, 10% of 25 is 2.5.
1% of 10 is 0.1, 10% of 10 is 1.
So do you have a sample size of 100 lenses? If you have 100 lenses, then you could say the issue is less than 1%.
If you had a sample size of 1000 lenses you could then say the issue is less than 0.1%
With a sample size 25 or under, it could just be luck. One or two SDM lenses not failing in 25, I don't think that would be a good bet when there are other larger samples that show an issue. At least we do know there are more than 100 lenses on DPR and here.
I think a lot of the complaints wouldn't even come to light in places that have longer warranties. It seems those with the one year warranties are the people that post, "whew, my lens failed, but thankfully it is under warranty", or "Crap, my lens failed and the warranty just expired". The others are mostly, "my lens failed and the warranty repair is taking months", or "my lens failed and the repaired lens failed". That leaves a lot of room under the bridge for failed lenses not to be reported.
It is your money, spend it as you want. I personally think you better have or buy an extended warranty.
Thank you
Russell