CZ 24mm F/1.8 buyers beware - check your lenses before leaving the shop

That arc is nothing but an internal reflection off one of the many glass surfaces inside the lens. It is not fungus, it is not dirt, it almost certainly is not a defect of any kind. The user has blasted the poor lens with an extremely bright light source(s) (see the blown-out circular spot-like reflections on the lens surface), then tilted it to an angle which is completely irrelevant to its ability to form images, then misinterpreted some innocent arcs of light. Look at the irregular highlight arcs on the filter threads. There are metal rings and threads inside a lens, which can give the same effect, but get further deformed by the glass.

Take a look at the weird ring on this Nikon zoom lens. It's another reflection caused by interaction of a bright light source with the lens optics:

Nell27 said:

i3c said:

Makes you wonder at the value of that little signed certificate that comes in the box.

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I'm sure they're good lenses, I just don't think I'd keep one that came to me with a defect. No matter how small or insignificant.

Like I said, everyone is different and maybe I'm just being ridiculous but that's the way I am. Can't help it.

I might feel different if it was an inexpensive lens but at the current price I'd want near perfection.

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I completely agree. I just find it ironic that Sony provides "quality assurance" certificates with lenses that are clearly sub-standard. Did someone really inspect that lens before signing the card?

I have a Zeiss e-mount 24mm coming. If it is less that pristine it's going straight back.

I've been buying photo gear for over thirty years and I've never really had much trouble. I've read reports of "bad copies" of lenses with scepticiscm. But after seeing a couple of poor samples from Sony I've come to think that they've gotten a bit sloppy.

(That said, I'm not seeing anything untoward in the example images above. Not saying there is nothing there -- I just dont see it.)

Guys, its not a reflection, it only looks like one in the photo because of the harsh lighting. I had to use a torchlight from the side to make it visible. When i turn the lens around to the other side of the radius, there is no white arc. I googled pics of fungus in lens and i see furry, veins/roots-like extensions & fluffy stuff. This one looks more like a layer of dust resting-on one side of the arc-edge of the inner barrel rim.

I understand that in the west, return/exchange policies are an accepted norm, I've read that most can even exchange multiple units and in the end opt for a refund and its done without a hitch. But things dont work this way in Asia, especially in a third-world one in the Indochine region. Even back in my own Asian hometown, the shop will direct you to the manufacturer instead of giving a one-to-one exchange, thats the SOP. Im normally an extremely anal person when it comes to goods condition and a very expensive one at that, but there was no arguing/raising of voice/banging tables at the store despite my unpleasant experience because the staff are pleasant and helpful, no hoodlums. Its unfortunate that one has to break the Sony sticker seal on the box to inspect the lens AFTER making payment. I've seen fungus in one of my bridge cameras before and when i see the white-arc on the CZ2418 it doesnt raise the same alarm bells as it did with that (i had it cleaned at cost). Regardless, i'll see if i can get a refund or just let SSC investigate and rectify the issue on Monday before i take further action.

Here's what I think you are seeing: the edges of some lens elements, which are ground, but not polished the way the refracting surfaces are. Some people don't realize that pieces of optical glass are not shiny and clear until they are polished. There is no need to polish the edges of an element, so it remains rough, like a piece of ground glass.

On some lenses, the edges of the elements are blackened with paint, but I wouldn't expect that on cheap consumer-grade zooms.

KM Legacy said:

Here's what I think you are seeing: the edges of some lens elements, which are ground, but not polished the way the refracting surfaces are. Some people don't realize that pieces of optical glass are not shiny and clear until they are polished. There is no need to polish the edges of an element, so it remains rough, like a piece of ground glass.

On some lenses, the edges of the elements are blackened with paint, but I wouldn't expect that on cheap consumer-grade zooms.

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I'm inclined to agree with you, to the naked eye it looks like "dust resting on the top edge of a glass panel of a fishtank", except I don't have the option of viewing it from another angle in the case of a lens. Or unpolished frame edges as you mentioned.

Thank God all's well that ends wel!. Was informed that the shop managed to sourced for another unit of the CZ24F18Z from Sony late this morning and told to go down and return the set with the "white arc". The salesman showed me the box sealed with the Sony sticker before cutting it to assure me its brand new like the previous unit. This time i brought my torchlight and scrutinized every part of the glass - prestine! From the lens number there's 619 units between the old and new lens, probably a different batch but "endorsed" with the same QC dude's signature. I'm glad it turned out this way as i was contemplating a lens exchange to the SAL 24mm F/2.0 (which the store has no issues with) as the next option. I wouldnt have minded since it'll mean i don't have to swop out the LE-EA2 since my other 2 lenses are both A-mounts as well, but they had no stock. Thanks to everyone who offered their valued opinions/advice and even posted pics for comparison. I'll never know what is the mysterious "white arc" but I'm just glad I didn't have to go thru the ugly refund route altho i wouldn't have minded a SAL lens exchange. I removed the tags so i hope it works out this round.

[URL='http://img.photobucket.com/albums/v282/artyboy/20120610_152444.jpg'] [IMG]http://www.dpreview.com/files/w/TS400?url=http%3a%2f%2fimg.photobucket.com%2falbums%2fv282%2fartyboy%2f20120610_152444.jpg [/URL]

My last comment was actually directed to teseg regarding his Sony zoom. I'm not so sure about your Zeiss lens. Better pictures (focused on the mystery arc) would help.

KM Legacy said:

My last comment was actually directed to teseg regarding his Sony zoom. I'm not so sure about your Zeiss lens. Better pictures (focused on the mystery arc) would help.

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Oops, my bad. But it still sounds relevant since it did seem that the white arc could be rough edges of the front lens element's edges as seen from the top.