p.1 #2 · What is this discoloration on the front element? (EF 300/4)
I don't know the answer. However, the front element is an optical flat—designed to protect the fragile real front element—and relatively inexpensive to replace. Well, if you can find the optical flat. It's a durable lens and tough to break. I bought the EF 300 4L USM new in 1994 and, finally, sold it last year to MPB. Was working perfectly but my newer zooms were out performing it so it wasn't used much.
p.1 #3 · What is this discoloration on the front element? (EF 300/4)
I'm not certain, but it looks like fungus.
Is it the 300 f4, not the 300 f4 IS?
As Gochuggi mentioned, the non IS lens has a protective front element.
If there is fungus there, it may also be on other elements.
If it's only the protective element, possible it could simply be removed. I don't know if there would be negative impacts on results, if not, it would be an easy fix.
p.1 #6 · What is this discoloration on the front element? (EF 300/4)
A lens with that degree of fungus would never be rated excellent. It's not usually just a matter of replacing the element with the fungus on it. Most folks say to keep a lens with fungus away from the rest of your gear. I have no idea if it's really true that it could spread from lens to lens or from your camera body to another lens but it's an easy pass for me.
p.1 #7 · What is this discoloration on the front element? (EF 300/4)
I have the 70-300 USM - I think that was the last/best version(?) - some say "L-like" IQ - the one with the LCD screen.
I'm considering replacing it with the 300/4 (I have other lenses to cover the other focal lengths).
In what way were newer zooms outperforming it?
In every way
Which ones?
Thanks...
Gochugogi wrote:
I don't know the answer. However, the front element is an optical flat—designed to protect the fragile real front element—and relatively inexpensive to replace. Well, if you can find the optical flat. It's a durable lens and tough to break. I bought the EF 300 4L USM new in 1994 and, finally, sold it last year to MPB. Was working perfectly but my newer zooms were out performing it so it wasn't used much.
p.1 #8 · What is this discoloration on the front element? (EF 300/4)
The 300/4 non-IS has much more even MTF from center to corner than most all SLR zooms in that range. Astimatism is quite low compared to most zooms also. If you are mostly interested in the center IQ and need modern AF and IS, then there are better options. It was my "goto" lens for tele landscapes for over 10 years. I also had two copies of the 300/4 IS, which has some advantages but typical edges/corners degradation of lesser lenses. Of course the Canon 300/2.8s are better yet.
p.1 #9 · What is this discoloration on the front element? (EF 300/4)
In the past, I was able to remove the fungus on 2 old FD lenses. It was more of a learning experience than anything else. It was easy to remove the front element, then I used a 50/50 mix of peroxide & ammonia on a q-tip. It took 2 or 3 attempts, but I eventually removed it.
Jim
p.1 #10 · What is this discoloration on the front element? (EF 300/4)
wsalopek wrote:
I have the 70-300 USM - I think that was the last/best version(?) - some say "L-like" IQ - the one with the LCD screen.
I'm considering replacing it with the 300/4 (I have other lenses to cover the other focal lengths).
In what way were newer zooms outperforming it?
In every way
Which ones?
Thanks...
It's certainly a good lens—often used it with Extender 1.4X for surfing and landscapes back in the day—but I found my EF 70-300 4.0-5.6L IS USM and EF 100-400 4.5-5.6L IS USM II a notch sharper and more flare resistant than my EF 300 4L USM was. Plus, I could easily hand hold the zooms and get sharp images. For me to get consistently sharp images with the EF 300 4L USM, I needed a tripod or had to lean on a solid object. Free standing, the VF was too shaky to compose accurately. Those with more steady hands are probably okay.
p.1 #11 · What is this discoloration on the front element? (EF 300/4)
I found found the 70-300L IS to be lacking in the periphery. I used it only a few times.
The 100-400 IS II replaced the 300/4, 300/4 IS, and 100-400 IS for me. It's the only one of those DLSR lenses i would use today.
