lens meter parametring

[mahmoud.hamza]

I am using 2 shinipon lens meter in my lab and there is a difference between the 2 one when I mesure By 0.01 step some times the difference is in SPH and some times in Cyl. the difference can be more then 0.1 diopter some times!!
thanks for your help

[Jacqui]

Are they both properly calibrated?? Use the same standards for both machines.

[mahmoud.hamza]

can you help me how to calibrate them?

[fjpod]

I'm not familiar with the brand you are using, but how can you tell if the instruement is off by .01?...that's too small an increment...unless you have a digital readout? If this is a basic optical lensometer, and the amount that the instruement is off varies from one read to the next, it is possible that the power wheel is just loose on the shaft. Even .1D is a small amount and is likely just due to operator variability.

[mahmoud.hamza]

I have 2 Shin-nippon lensmeter SLM4000 and SLM5000 one I am using them in the quality control step in my surfacing lab.
the prolem that the mesurment that I am making with the First SLM4000 is different then the SLM5000 when I use 0.01 step and espacelly in cyl

an exemple:
target +3.50
1st SLM 4000 +3.53 (+0.11)
SLM 5000 +3.51 (+0.00)


For your reference the SLM5000 is 3 years old and i did never make a calibration on it because I did not found the calibration set in in Tunisia, the SLM4000 Are new

[HarryChiling]

I have 2 Shin-nippon lensmeter SLM4000 and SLM5000 one I am using them in the quality control step in my surfacing lab.
the prolem that the mesurment that I am making with the First SLM4000 is different then the SLM5000 when I use 0.01 step and espacelly in cyl

an exemple:
target +3.50
1st SLM 4000 +3.53 (+0.11)
SLM 5000 +3.51 (+0.00)


For your reference the SLM5000 is 3 years old and i did never make a calibration on it because I did not found the calibration set in in Tunisia, the SLM4000 Are new

I have never worked on the model lensometers you own, but do keep in mind that all instruments will have a tolerance, and more than likely you have a tolerance of +/- 0.01D which can account for up to 0.02 difference between measuring the same lens.

[mahmoud.hamza]

but the difference that I have is 0.11!! it is not small difference !

[Barry Santini]

but the difference that I have is 0.11!! it is not small difference !

In my expereince with My Humphrey Lab 360, think "dust/smudges" in the laser path as the culprit for the 0.11 cyl.

FWIW

Barry

[mahmoud.hamza]

Barry can you please explain?

[mahmoud.hamza]

also another power :

sph -2.50
==> SLM 4000 => -2.60 (-0.1)
==> Essilo => -2.57 (-0.19)
It make me creazy !!!
:hammer::hammer::hammer::hammer::hammer::hammer:

[Paul van Wyk]

We do a calibration on all our lensmeters at least once a year , on the ones in QC we calibrate more often.

[mahmoud.hamza]

We do a calibration on all our lensmeters at least once a year , on the ones in QC we calibrate more often.

is there a standart procedure to calibrate a lens meter the supplier Of the SHIN NIPPON in our country can not help us !!!!