What to purchase next? Child portriature.

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An 85 1.8 should work great on your camera and get you a ton of crisp, beautiful shots of kids.

85mm1.8

800mm f/5.6, to avoid them throwing up on you . Just kidding! 85mm is amazing.

Elements would serve you just fine considering the cost of photoshop CS. As your skills/needs change you could always upgrade down the path.

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When I took pictures of my newborn daughter, I brought all these fancy portrait lenses with me, just to discover that a macro lens was what I really needed. Babies are incredibly small, the head of a newborn is about 10 cm in diameter, the hands and feet are even smaller!

The lens I used mostly was the EF50mm F/2.5 macro, since it was the only macro which autofocussed all the way to the macro range (you don't want to MF your baby, they move way too fast. Yes, I grew up with MF lenses and know how to focus manually).

So my recommendation is you first figure out which size kids you want to take pictures of and which magnification you will need. From there you figure out the focal length you are comfortable with, possibly go to a decent store and try out a few lenses in the range.

My take on the seminar...

The OP wrote:

"I have discovered a local photographer whose work I really admired... turns out that this photographer is doing a weekend seminar... for beginners/prof. The investment for that is about 850-... it is two full days (9-5) and snacks and lunch provided both days. I have no idea... it is a ton of money to be, but the information would be invaluable. What do you all think?"

That is a ton of money which, with your lack of equipment could be much better spent on some new gear.

Although the 85mm f/1.8 lens is a really nice piece of glass; I recommend basing your lens collection on a really top-notch medium-range zoom lens. Although I do love my17-55mm f/2.8 IS lens for general photography and use it as my "go-to" lens for general shooting, I would suggest a zoom with a bit longer end than the 17-55mm lens offers. I much prefer my 24-70mm f/2.8L for shooting people - especially in a studio.

The two medium-range zoom lenses that come to mind immediately are the 24-70mm f/2.8L and the less expensive, but very good, Tamron 28-75mm f/2.8 XR Di (I might have omitted a bit of Tamron's alphabet soup designation).

IMO, for shooting kids, the longer end is more important than the shorter end. You tend to get some distortion when shooting people with shorter focal lengths.

You can probably get a good used 24-70L for the $850 that you would pay for the seminar and you can get a Tamron for about $500 or so. If you choose the Tamron, you could (with some luck and careful shopping) get a lighting setup for the extra $350.

If some of you are getting ready to hit your keyboard denying that an adequate lighting setup can be had for $350 or less; I purchased an excellent 3-monolight German-made Multiblitz Mini 200 set for $200 plus a few bucks shipping on eBay. In addition to the 3 monolights; the set included barndoors, snoot, grid, filter holder and set of colored glass filters - all in a fitted fiberglass suitcase. The equipment was in primo shape and Multiblitz continues to support this gear with replacement parts such as flash tubes

Throw in 3 inexpensive stands ( the Monolights-200 are not heavy) and a large window shade on a stand for a background and you are equipped for some really professional looking child portraiture.

In addition to studio shooting, the constant f/2.8 aperture of either of the above lenses will allow available light shooting also.