Canon 55 250mm Ef S Lens
What is the difference between a Canon EF-S 55-250mm which is with my SLR lens and a new 35mm EF 80-200mm my old?

just got back a digital SLR camera is my old 35mm lenses compatible? What is the difference.

In an APS-C Canon Eos Digital can use both the old EF and EF-S. The EF-S has a shorter approach to the rear (the rear element is closer to the sensor), which compensates for the smaller sensor. Therefore you can not use the EF-S 35 mm in a while you can use the EF in digital. There are other differences between the old EF and EF-S, including coatings individual chemical elements. EF An old (circa 1987-2000) most likely do not have layers that remove certain artifacts from your digital photos. But this minor drawback is not particularly large and can be compensated.