Most bang for budget buck - Pro Optic 8 x 42 8.3 ED? (1 Viewer)

This is a bit of a duplicate post. The HD in ZRS HD is for High Density. There is a rare earth element in a lens in the eyepiece assembly. Its purpose is to assist in flattenting the field. Sorry, I don't know for sure which rare earth element.

You probably mean Lanthanum. But that in itself does not make for a flat field. Typically binoculars use a 4-element design in the eyepiece. To get a true flat field a 5th element is required and that usually adds weight and size to the ocular. However, aspheric designs have now become inexpensive and can simulate a "flat field" by correcting other more image-damaging aberrations, especailly in bino's sporting wide AFoV.

Rick

RJM said:

You probably mean Lanthanum. But that in itself does not make for a flat field. Typically binoculars use a 4-element design in the eyepiece. To get a true flat field a 5th element is required and that usually adds weight and size to the ocular. However, aspheric designs have now become inexpensive and can simulate a "flat field" by correcting other more image-damaging aberrations, especailly in bino's sporting wide AFoV.

Rick

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Hi Rick and Steve

Lanthanum is something i have only seen referred to in a small number of binoculars but many more eyepieces
The link below is to a pair of German made Praktica Pentacon reverse porro's that possess some Lanthanum elements (these bins are not to be confused with the host of cheap cloned Chinese Praktica variants )
I own a pair of these and they are excellent wide angle compacts
I dont know for sure what the Lanthanum eyepieces actually do in these binoculars but apart from soft edges imho the image is better than other reverse porro compacts i have looked through at this price

http://www.scopesnskies.com/prod/pentacon/lanthanum/compact-porro/binocular Lanth-8x25wa.html

Maybe Lanthanum will re-emerge as the next buzzword in the ever morphing optics world just lately ?


Regards
RichT

There are already Lanthanum crown (LaK) elements in a lot of bins. It just doesn't get a lot of mention.

It helps control the lateral CA in the ocular (that's why it's used in astro EPs too).

IMHO there's not much point in adding a ED glass objective if you don't design an ocular to reduce lateral CA. This is what the Chinese ED bins have been doing.

The aspheric designs mostly use a hybrid CR39/glass element where the CR39 (plastic) is shaped with aspheric shape.

The 2009 ZRS did have a LaK field flattener in the design and that contributed to the red bias. ZR have changed this (i.e. the red bias is gone) but I'm still not sure if they retained the LaK field flattener or changed the ocular design to get a similar feature.

You can put a field flattener before the roof prism or after it or add an extra element to the ocular and use that extra degree of freedom to get a flatter field (it's one of the many trade offs you can make).

birdazzLED how about you just send thoughts defective EDs back and get a good set to test you had my hopes up now I'm falling into despair. I need my cheap ED fix and can't be got up here in Canada The shipping and tax can add 50% so I need you southern boys to do the ground work (weed out the crap) grin!

Thank Alan : PS please don't take me to seriously.

hehe ok but seriously, I have a very hard time telling the difference between the ZRS and ED2 under most conditions. If I could only look through the bins and not touch them or see the tubes, I could only guess which is which.

I believe the Pro-optic is the same as the Viking. Some reviews here

Yeah, I sent them back. Strange thing is the packing slip says, "serial number 1". I can speculate wildly with that so I'll leave it at that.

birdazzLED Thanks , that serial #1 may not be a good sign or look at it this way your first to try some thing new. Hope you get a good set this time keep us posted.

Best Alan

I found the "most bang for budget birding buck" to be the ZRS and the ZENed2. I couldn't help myself and "splurged" with my credit card - I opted for the ZENed2! B