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02-24-2014, 11:13 PM   #1
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lens rating formula

Hey everyone. I was trying to decide between two different lenses at the end of last year, and I had a very hard time making up my mind. I put all the lenses and the reviews into excel to compare them, but I didn't like how the ones at the top of the list for ratings, were there because one person reviewed the lens, and gave it a ten. I also did not have a steady stream of money coming in, so I wanted a way to factor in price as well. I ended up making formula, that would give their rating more weight if there were more people who reviewed it (the idea being that if 100 people give it a 9.5, its probably a more well liked lens than a lens with 1 reviewer and a 9.5 score). I also added a part in where I could change the how much the price of the lens factored into my rating, so I could change the weight of the cost vs. rating.

I was happy with what I came up with, so I figured I'd share it with anyone else who wanted it.

a few disclaimers first.

I don't think that this is a perfect system, or one that is better than anything that already exists, I made it to help me make a decision, but I also backed that decision up with much research about the lenses I was considering and not just numbers.

I'm not the best with excel, feel free to mess around with it as much as you want, and make it fancier

The list might not be exhaustive, I haven't updated it in a few months, and there may be things I missed, (I apologize if there are any data entry errors)

use at your own risk


Finally,

To change how much the cost of the lens weighs in on the new rating, enter a new number in the box under "Rating Adjusted Weight."

The number will be multiplied to the weight of the adjusted rating against the cost. For example a "2" would mean that the new rating will be twice as important as the cost, and so on.


(Make sure to hit enter after you have added a new number)


You can also use the drop down arrows at the top of the table to sort the columns.


enjoy!
(you will need microsoft excel to open the file, other programs may open in, like google docs, but I can't confirm how well they work)

https://drive.google.com/file/d/0BwrPgxGKuf-Dazd2Zkh4U2x5ZXM/edit?usp=sharing


(the forum attachment system wouldnt accept the newer excel file types, and when I saved it in an earlier format, it broke some of the formulas)


Last edited by cpritchardv; 02-25-2014 at 09:48 AM. Reason: clarification
02-25-2014, 12:07 AM   #2
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Well that's one long list, you've certainly done your research! Thanks for sharing, might come in handy sometime
02-25-2014, 08:05 AM   #3
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I have posted a number of reviews. I have to say I think the dyxum forums minolta/sony lens reviews 1-5 point system is better. 1-10 is too random, most ratings cluster around the 8/9 mark and 10 is given out too readily, too many individuals exhibiting "confirmation bias" IMO (see this weeks Horizon on BBC iplayer) , or simply an impulse to advertise their satisfaction with their acquisition: "I've bought the lens so it must be good".

1-5 breaks down more readily (roughly) into

5 = top, zeiss, leica, top pro lenses etc
4 =good to very good/pro level lenses
3 = normal quality, consumer lenses
2 = obvious deficiency/deficiencies in performance
1= substandard, reject.



But its too much hassle to change everything onthis site, so work with it.

PS i don't have excel or ms office (I use open office) so not sure what to do with your link

Last edited by marcusBMG; 02-25-2014 at 08:11 AM.
02-25-2014, 12:50 PM   #4
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QuoteOriginally posted by marcusBMG Quote
PS i don't have excel or ms office (I use open office) so not sure what to do with your link
OpenOffice should be able to do the job.

02-25-2014, 01:16 PM   #5
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Quite honestly, there are three types of people that rate lenses.

Those who rate their lens a 10 to self justify the price they paid, those who rate the optically highest specified lens as 10 because they want the absolute best at any price, and then people like me who would rate a $5 barging bin lens as a 10 because in terms of $/ performance criteria, no body can argue.

The fact is, the price vs performance curve is so steep, and minimum lens quality is relatively speaking also very good (ok there are real dogs out there but...) so the big issue is, how much quality are you willing pt pay for?
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