Looking for advice on a zoom lens.

Camera is 5D and will probably upgrade to another full frame like 6D or a mirror-less full-frame from Canon (If it gets out ever). Currently have a 50 and 100mm primes. Looking for a bit more reach. Budget around 500$. Looked through my options and found 70-200 f4 NON-IS, canon 70-300 NonL and Tamron 70-300 VC. Any advise on which one will be good for me?

70-200 IS would be helpful. Once you "reach out", and with lower ISO of the 5D, I think you'll want it.

The new 70-300mm USM II is the best bargain going in Canon zooms. Lightning-quick, dead-accurate focus, and optically excellent. I got one from Canon Refurbished for $379. You get 50% more reach than the 70-200, and modern IS, and IQ on par with the 70-200, for a few $$ less than the 70-200. I sold my EF 70-200mm f/4L IS USM after getting the 70-300 II.

Thanks Tom. I will look into Canon 70-300 II.

Bassat wrote in post #18597048
The new 70-300mm USM II is the best bargain going in Canon zooms. Lightning-quick, dead-accurate focus, and optically excellent. I got one from Canon Refurbished for $379. You get 50% more reach than the 70-200, and modern IS, and IQ on par with the 70-200, for a few $$ less than the 70-200. I sold my EF 70-200mm f/4L IS USM after getting the 70-300 II.

I would love to see the new 70-300 compared to the 70-300L. The used price for a 70-300L has already fallen to around $700. If the 70-300 USM II is the same or better, my 70-300L take even a greater hit.

Phoenixkh wrote in post #18597251
I would love to see the new 70-300 compared to the 70-300L. The used price for a 70-300L has already fallen to around $700. If the 70-300 USM II is the same or better, my 70-300L take even a greater hit.

My take on the 70-300 L vs II showdown. $700 for used vs $379 for new (refurb). Roughly equivalent IQ, AF, and size/weight. Money counts. I'm done.

The 70-300L is way-good at the short end. No argument there. So is the 70-300II. Take a look at Dustin Abbott's review of the II; it is very interesting.

I think the main take-away it to take each lens' reputation with a grain of salt. The 70-300L is, according to some, the greatest invention since fire. The original 100-400L gets dinged hard for being mediocre, at best. Going by Opticallimits.com (FKA: photozone.de) reviews, the 100-400L is better at 300+ than the 100-300L is at 300. What? Yes, the crap lens is better than the venerable 70-300L. The 'good' 70-300L is still fetching more on the used market than the 'bad' 100-400L. Go figure. People are weird.

Look at my take on the 70-300II compared to one of the greats (70-200 f/4L IS USM), here: https://photography-on-the.net …/showthread.php​?t=1489524. Short story: buy the 70-300 II. And don't forget, I had just paid good money for this lens, so of course my review is not biased, AT ALL! Honestly, I was looking to move to lighter gear. Shooting the 70-300 II on an 80D allowed me sell my 6D, 70-200 f/4L, and at least think about selling the 100-400L. The 100-400L is way better than its reputation, and certainly better than its current used price. I'll keep it until field mice make a nest in it before I sell it for <$600. I paid $1700 for that lens 10+ years ago. It is still as good as it was then.

Bassat wrote in post #18597272
The 100-400L is way better than its reputation, and certainly better than its current used price. I'll keep it until field mice make a nest in it before I sell it for <$600. I paid $1700 for that lens 10+ years ago. It is still as good as it was then.

I agree. If this is the case, and the OP can come up with a bit more scratch than his $500ish budget, why not get a used copy of the 100-400L? It's my go-to sports lens and it's fine for birding and wildlife (in good light). It also gets him out to 400mm at the long end with excellent IQ. Yes, the new version II is amazing, but it costs a fortune and some of the new Sigma and Tamron offerings can be considered on par, but for the price these things are going for recently, I'd say grab one if you can.

The 100-400 simply doesn't resolve much detail on the higher density sensors like newer lenses including third party glass. Once you crop and do anything that requires getting into the image, it shows its age.

It's up for comparison at the-digital-picture. A bit weak at the short end, but decent at the long.

TeamSpeed wrote in post #18597316
The 100-400 simply doesn't resolve much detail on the higher density sensors like newer lenses including third party glass. Once you crop and do anything that requires getting into the image, it shows its age.

My first reaction to this claim was HOGWASH! Then I looked through my LR catalog. I must say, I have to agree with you. This shot is a 100% crop of my wife talking to my SIL. I can see her chicken pox scars, and the makeup in her wrinkles. (If I disappear from POTN, you'll know she read this!) I can see his sunglasses in hers. This is 6D, 100-400L at 400mm, from the opposite side of a football field. I can't find anything even close taken on my high-density 80D.

Chris.R wrote in post #18597326
It's up for comparison at the-digital-picture. A bit weak at the short end, but decent at the long.

Am I the only one who finds this just a tad ambiguous?

I don't know... my 70-300L is what got me into bird photography. This guy showed up in our backyard:

IMAGE LINK: https://flic.kr/p/nyc8​eS

IMAGE LINK: https://flic.kr/p/iBis​Sn

Kim, I think you (and your owl) sum up the issue quite nicely. Good glass is getting less expensive, and less expensive glass is getting better. The 70-300L was a HUGE step up from the 70-300 micro-motor-fake-USM. I bought my 100-400Lc to replace the old 70-300. At the time, it was my only choice, and it cost my $1700. A lot of shooters can't afford top-notch glass like the 100-400L II. If something like the 55-250 STM or 70-300 II gets the job done, for less money, people will use it.

I have a few 'good' lenses, and a lot of consumer-grade lenses. As wyntastr suggests, the 100-400Lc @ $600-700 may be the best bargain going for inexpensive long glass.

Check K&H for used gear.

With the long list of "II' L glass around, you can snag something excellent in the "I" series and be very content.

70-200 is one example.

TeamSpeed wrote in post #18597316
The 100-400 simply doesn't resolve much detail on the higher density sensors like newer lenses including third party glass. Once you crop and do anything that requires getting into the image, it shows its age.

While I'm sure this is the case, the OP is currently shooting a 5Dc with plans to upgrade to a 6D, both with sensors that wouldn't be considered "modern" in the strictest sense.
I just purchased a brand new 6D and am super pleased with the sharpness the ol' 100-400L produces. (example below)
I think the (now) budget 100-400L mkI paired with his current 5D or the 6D future upgrade would make a lot of sense and provide years of rock solid service.

IMAGE LINK: https://flic.kr/p/25gr​mwX