FrankS
Registered User
Please see here: http://dictionary.reference.com/search?q=double-blind
also see the single-blind lnk
You have to do some mental manipulations to apply it to lens testing.
also see the single-blind lnk
You have to do some mental manipulations to apply it to lens testing.
xayraa33
rangefinder user and fancier
Biggles said:
$150 USD and higher depending on condition , late black ring ones bring in more, these are all non - collapsable 50mm/f2s. The early collapsable ones go for $700 USD and higher, again depending on condition.
BrianShaw
Well-known
Frank,FrankS said:Double-blind means that the person doing the testing is also not aware of the variable (in this case which lens) being tested.
This is done mainly in clinical trials of drug effectiveness where the placebo effect is significant. If the researcher knows that he/she is administering the drug as opposed to the placebo (sugar pill) his/her manner may impart a better feeling to the patient.
Double-blind lens testing is not necessary (or practically possible.) The single-blind procedure is perfectly acceptable.
Sorry for being/sounding nit-picky!
Sorry to be nit-picky... but here is the definition of double-blind and single-blind:
"In a single-blind experiment, the individual subjects do not know whether they are so-called "test" subjects or members of an "experimental control" group. In such a trial there is a risk that subjects are influenced by interaction with the researchers - known as the experimenter effect.
In a double-blind experiment, neither the individuals nor the researchers know who belongs to the control group. Only after all the data are recorded (and in some cases, analyzed) may researchers be permitted to learn which individuals are which. Performing an experiment in double-blind fashion is a way to lessen the influence of prejudices and unintentional physical cues on the results."
But, as you said... only a single-blind experimental protocol is required for equipment testing. Unless, however, one thinks the lens might be biased if it knew who was testing it ;-)
Alec
Amateur
I love it when three bearded respectable professors have an argument!FrankS said:Sorry for being/sounding nit-picky!
I think I'll side with you - bear with me for a few days while I grow my own beard.
BrianShaw
Well-known
Alec said:I love it when three bearded respectable professors have an argument!
I think I'll side with you - bear with me for a few days while I grow my own beard.
I love it even more when the bearded professors argue... and are all arguing the same opinion!
FrankS
Registered User
I also said that some mental manipulation is needed to apply the definition to lens testing.
With single blind methodology, only the test subjects (viewers of the lens test results) are unaware of which lens produced which result. (That's the idea after all so that biases won't influence preferences.)
With double blind methodology, the test subjects (viewers of the lens test results) and the experimenters (those conducting the lens tests) are unaware of which lens they are testing. (That's just silly.)
With single blind methodology, only the test subjects (viewers of the lens test results) are unaware of which lens produced which result. (That's the idea after all so that biases won't influence preferences.)
With double blind methodology, the test subjects (viewers of the lens test results) and the experimenters (those conducting the lens tests) are unaware of which lens they are testing. (That's just silly.)
Last edited:
BrianShaw
Well-known
Yup... no disagreement.
FrankS
Registered User
... Whew!
raid
Dad Photographer
Frank: Your stated definition is correct, and I just revamped the definition for our purposes here.
FrankS
Registered User
Good. Just to summarize then, when conducting lens tests, it is not with a double-blind methodology since that would mean that the testers/experimenters are unaware of what they are testing.
The test may be single-blind where the viewers of the results are not aware of which lens was used for each result, and they must state preferences without that knowledge.
Or the test may show the results with the lens info (as we have done here so far) and viewers may be influenced by their biases (say , pro-Leica) when stating their preferences.
The test may be single-blind where the viewers of the results are not aware of which lens was used for each result, and they must state preferences without that knowledge.
Or the test may show the results with the lens info (as we have done here so far) and viewers may be influenced by their biases (say , pro-Leica) when stating their preferences.
Biggles
My cup runneth amok.
xayraa33 said:
Thank you, sir. I loathe collapsibles from a practical standpoint. I'll look for a rigid one.
VinceC
Veteran
The prices seem to vary because of low turnover and sporadic demand, and I don't follow LTM prices too closely. But around $300 would seem to be past the upper limit of reasonable. You can often get an old Tower or other screwmount camera attached to the f/2 Nikkor for that amount or a bit more.
xayraa33
rangefinder user and fancier
the 50mm/f2 Nikkor LTM is a fine lens, I have an example of its use in my gallery,they do come up for sale on that auction site very often.
Trius
Waiting on Maitani
Single blind, double blind, quadruple blind ... I still haven't seen any of x-rays photos which illustrate the original post. Or am I all blind?
Gabriel M.A.
My Red Dot Glows For You
And I thought a double-blind test went something along these lines :
(found at cartoonstock.com via google)
:
Last edited:
C
ch1
Guest
gabrielma said:And I thought a double-blind test went something along these lines
Hey, I know that guy, he does the eye tests at the motor vehicle bureau!
x-ray
Veteran
Single blind, double blind, quadruple blind ... I still haven't seen any of x-rays photos which illustrate the original post. Or am I all blind?
I had a full schedule today and will be on a business trip untill monday. When I return I will reshoot the test wit the same batch of film and run it, scan the two in the same scan and post them.
Please don't get me wrong, I love the Summicron. I've made some great images with it and it's no less of a great lens because the Nikkor has less flare. It's not like 50% more but there was a noticable difference.
I really don't think I have a bias as to lens or camera maker. I've ownes so many systems over the past 40+ years as a professional. I've always loved some of the Nikkor glass (24mm 2.8, 35mm 1.4, 50mm micro, 85mm 1.8 (old version), 105 2.5 (old version) and the 180mm 2.8 ( any version). There are others like the 35mm f2 and 24mm f2 plus a few others that I never felt were more than average. The same is with Leica. I've never had a love for the 28mm's or tele elmarits although they are good lenses. However I love my 90mm 1st version Elmarit and later versions of the 35mm f2 Summicron. I particularly loved my 35mm 1.4 Summilux first version and 21mm 3.4 Super-Angulon. I liked the 21 SA over my 21 Elmarit. I wouldn't say these lenses were sharper than the others but had a special character or quality that I love. I don't own any of the new ASPH lenses because I feel they're too harsh and I like the character or personality of the older glass.
To me what makes a superior lens is a combination and proper balance of characteristics of a lens. Contrast doesn't have to be extremely high and resolution doesn't have to be super sharp. To me it's all in the balance of sharpness, contrast and illumination fall off as in the 21mm SA.
I feel the same about my canon glass. Some of it's outstanding and some average
My little informal test hasn't burst my bubble about my 50mm Summicron. It still makes stunning images.
http://www.rangefinderforum.com/photopost/showgallery.php?cat=5045
I had a full schedule today and will be on a business trip untill monday. When I return I will reshoot the test wit the same batch of film and run it, scan the two in the same scan and post them.
Please don't get me wrong, I love the Summicron. I've made some great images with it and it's no less of a great lens because the Nikkor has less flare. It's not like 50% more but there was a noticable difference.
I really don't think I have a bias as to lens or camera maker. I've ownes so many systems over the past 40+ years as a professional. I've always loved some of the Nikkor glass (24mm 2.8, 35mm 1.4, 50mm micro, 85mm 1.8 (old version), 105 2.5 (old version) and the 180mm 2.8 ( any version). There are others like the 35mm f2 and 24mm f2 plus a few others that I never felt were more than average. The same is with Leica. I've never had a love for the 28mm's or tele elmarits although they are good lenses. However I love my 90mm 1st version Elmarit and later versions of the 35mm f2 Summicron. I particularly loved my 35mm 1.4 Summilux first version and 21mm 3.4 Super-Angulon. I liked the 21 SA over my 21 Elmarit. I wouldn't say these lenses were sharper than the others but had a special character or quality that I love. I don't own any of the new ASPH lenses because I feel they're too harsh and I like the character or personality of the older glass.
To me what makes a superior lens is a combination and proper balance of characteristics of a lens. Contrast doesn't have to be extremely high and resolution doesn't have to be super sharp. To me it's all in the balance of sharpness, contrast and illumination fall off as in the 21mm SA.
I feel the same about my canon glass. Some of it's outstanding and some average
My little informal test hasn't burst my bubble about my 50mm Summicron. It still makes stunning images.
http://www.rangefinderforum.com/photopost/showgallery.php?cat=5045
x-ray
Veteran
I would be curious how the CV Nokton 50mm 1.5 would compare. Any experiences shooting into strong light sources? Anyone have a late summicron and 50mm Nokton?
http://www.rangefinderforum.com/photopost/showgallery.php?cat=5045
http://www.rangefinderforum.com/photopost/showgallery.php?cat=5045
Trius
Waiting on Maitani
x-ray: No problem, I was just curious to see the images. Your gallery is wonderful, no matter what lens, so I understanding what you're saying.
21mm SA? Sigh. I owned one and used it on an M3. It was great. The Zuiko 21/f2 was different but "equally" special for me. Still have that one.
Earl
21mm SA? Sigh. I owned one and used it on an M3. It was great. The Zuiko 21/f2 was different but "equally" special for me. Still have that one.
Earl
dreamsandart
Well-known
The first Leitz/Leica lens I owned was a 50 Summicron DR, beautifully made, but the lighter weight of the '69' 11817 version that focused to 27" without the extra eyes has been my main 50 now for 30 years. Although the 11817 is well made its not 'glamorous' by Leica standards, but still I find myself fairly regularly amazed at the image quality that comes from this classic late 60s glass. I've also owned the original collapsable 1st version, and the one 'flaw' in all 3 Summicron 50/60s designs would be the 'veiled flare' that can cover the whole frame under certain strong direct light on the front element, with each generation handling it better than the last.
I've also used a Summilux over this time and in contrast handles strong light on the front element very well.
As for my Nikkor experience I've used a late 50s 50mm f1.4 LTM and 35mm f2.5 that are some of the sharpest lenses I've used, handle flare very well and are also very compact and superbly made. 'Ideal' LTM lenses [on a M-series also] and as good as the Leica Lenses in many ways.
The one criticism about 50 Nikkor glass is that compared to the Leitz glass it is just not as 'smooth' looking - talking bokeh here. It can look very 50s/60s classic, but its quirk are those times with certain highlights - usually in daylight and wide open, (slow film and high shutter, hay I like bokeh - when the background turns to 'fried doughnut rings'. Nikkor glass from the rangefinder days was considered great stuff back then, I don't think anyone - that knew - thought it inferior to Leica glass, and in the LTM days at least the 50 f1.4 lens was thought of as 'the best fast lens' around.
Glass from Leitz and Nikkor have their weaknesses and strengths, both are great fun to use.
I've also used a Summilux over this time and in contrast handles strong light on the front element very well.
As for my Nikkor experience I've used a late 50s 50mm f1.4 LTM and 35mm f2.5 that are some of the sharpest lenses I've used, handle flare very well and are also very compact and superbly made. 'Ideal' LTM lenses [on a M-series also] and as good as the Leica Lenses in many ways.
The one criticism about 50 Nikkor glass is that compared to the Leitz glass it is just not as 'smooth' looking - talking bokeh here. It can look very 50s/60s classic, but its quirk are those times with certain highlights - usually in daylight and wide open, (slow film and high shutter, hay I like bokeh
- when the background turns to 'fried doughnut rings'. Nikkor glass from the rangefinder days was considered great stuff back then, I don't think anyone - that knew - thought it inferior to Leica glass, and in the LTM days at least the 50 f1.4 lens was thought of as 'the best fast lens' around.Glass from Leitz and Nikkor have their weaknesses and strengths, both are great fun to use.