06-06-2018 10:01 PM
How did the front element come to be missing?
I am not familiar tith the non is version but the other one is very expensive. I wouldn't use one with no front element because you will get dust and dirt inside it.
06-07-2018 01:27 AM
There's 1 on ebay going cheap other than the glass missing the lens is mint its being sold by a trusted seller don't know if I should go for it and whether i can get new glass
06-07-2018 08:47 AM
The answer is no it will not work. The front glass is part of Lens Group 1. Why would you even think Canon would put lenses in their lens that is doesn't need?
06-07-2018 09:23 AM
"ive been told that it is just a plain glass element NOT an optical element on the mk1?"
It may be but I count 10 lenses in 8 groups. That tells me it is needed.
06-07-2018 10:57 AM
ive been told that it is just a plain glass element NOT an optical element on the mk1?
Even plain glass has a refractive index. Even if the element's only purpose was to have coatings painted on it, the rest of the lens may have had to account for its presence.
And why isn't the element there anyway? Doesn't its absence suggest that the lens has been dropped? So what other damage might there be? Unless you're a qualified lens repair person with considerable experience on Canon lenses, I think buying it would be a very risky proposition.
10-30-2019 10:30 AM
The front element is protective only BUT it is coated and it needs to be there to protect the rest of the lens. It was designed so that the front element is fairly inexpensive to replace since it isn't truly part of the lens groups involved in focusing (the 10th element in your lens is another flat element) but you need to check with a camera shop that repairs an older Canon lens to find out how much it would cost to replace the front element I would also want to be absolutely sure that the lens otherwise works, that front element could have been broken by a light tap to the glass or from a hard hit that may have damaged more within the mechanism. It would have to be really cheap to take a chance.
Because of the size of the front element on these fast, long telephoto lens a front filter isn't practical so the first element is often a sacrificial protective piece while the actual filter is at the camera end of the lens.
That being said in terms of purchase caution of this damaged unit, I have the later IS version of the 300 2.8 and it is my favorite sports lens for high school football and soccer; a little easier to manage the FoV compared to a 400 2.8 but enough reach, especially with current high pixel count cameras. On an APS-C sensor camera, it is as long as you want for most action sports and will make framing the action more difficult in many cases with APS-C. This lens works extremely well with a 1.4X because its native sharpness is so good. The Canon 300 2.8 is an amazing lens.