There are not enough details in that listing. It also seems to be very expensive for what it is.
Thanks I’m trying to find a lwd 160/. Objective
I want to look at petri dish from below
Most LWD objectives are designed for looking at the surface of samples, often referred to as ‘metallurgical’ objectives, as opposed to ‘biological’ objectives designed to look through a coverslip. Whether there is a layer of glass between the sample and the objective, and how thick it is, will change the lens design needed.
The second line on a biological objective marking is usually 160/0.17 or /0.17, meaning that they are designed for a 0.17mm thick coverslip. LWD metallurgical objectives are 160/- or /-, meaning they are is designed for nothing between the object and the lens.
I know of one lens design that is intended for 1.1mm glass thickness, available in 20× or 40×, AE Objective - CCIS® Plan achromatic objective LWD PL 40X/0.5 (WD=3.0m | Motic Microscopes . They are not cheap, but not as high cost as many other LWD, and designed for thick glass. They are also infinity corrected not 160mm, but that just means using the other optics module in the Openflexure Microscope.
Of course if you are looking through the base of a Petri dish it needs to be very flat or it will distort your images, particularly at 40×. For this kind of application people usually use Petri dishes with windows in the base that are the thickness of a normal coverslip, and then use normal biological lenses.
I found a plan objective 40x/0.60. 160/1.5
Am I right to infer the 1.5 refers to expecting a cover interface of 1.5mm ?
There is someone selling that exact objective you’ve linked for 60 as well on eBay
Yes. Take a look at this one:
Thanks I got the LWD PLAN 40/0.60 160/1.5 objective and it works perfectly as expected.
There are some objectives with a weird dial on it with numbers, what do those do? such as this one linked.
variable focus? zoom?
Variable cover glass thickness. That one says 160/0.11-0.23, the dial is marked in 100ths of a mm.