I bought a Canon camera to replace one that failed after an alkaline battery leaked in it. The replacement camera gave me lots of trouble with batteries, claiming they needed to be replaced even when new and fresh. Turns out the battery door design on some Canon cameras was defective. Shimming mine up to keep the contacts tight was the fix.
While searching for an answer, I went searching eBay for rechargeable AA's, because alkalines were getting expensive. The 2 AA NiMH batteries that came with the camera were labelled 3000mah, which I knew was fake. I didn't call out the seller for it because it was a camera I was buying.
While searching eBay I came across lots of offers for 3000mah AA NiMH batteriers. There is no such thing and never was. The highest capacity AA's are about 2500mah and those are fragile. AA's with around 1500mah are a decent trade between capacity and recharge life.
eBay apparently doesn't care that their sellers scam people. To knowingly allow the sale of something that does not to exist is outright criminal, so I used a Target gift card I got at work and went retail shopping for rechargeable AA's. I got a pack of 4 1400mah Energizer AA NiMH for $10. Screw eBay.
There are several 'smart' AA/AAA tester/rechargers on the market. I have an AccuPower IQ-328 and tested the "3ah" AA's that came with the camera. Both came in about 575mah. That's right, less than 1/5 the rated capacity, but close to what I guessed, since they looked like generic solar path light cells, which are usually 600mah.
I'm testing the Energizers now and will post back their real capacity when the test is done.