So first child is due in a few short months
CONGRATS!!!!!
and I am looking to upgrade my lens for taking what I plan to be many photos of both this child and (hopefully) more to come!
Sounds familiar...
Currently have t4i with 18-135 stm kit lens. I've already read a number of other posts on this topic. My questions are:
1) What would be a good lens and focal length for newborn/baby photos? I am considering the 50 /1.4 or 40 /2.8 stm. Price excluded, which would work best for this purpose? We have a newly built home, is pretty roomy with good natural light (other than the fact that this time of year in Michigan it's dark by the time I'm home from work.....)
The strengths of the 18-135 STM are
- the enormous focal range
- silent/fast focusing - especially helpful for video
- the IQ (Image Quality) at wide to medium focal lengths (this is where it performs best, 40-50mm included)
The weaknesses of course are
- not very "fast" in terms of aperture
- reduced (yet still respectable) IQ at longer focal lengths
Babies and toddlers are small. Many people don't anticipate just how small they are and tend to think of lens needs based on traditional photography needs. A "head and shoulders" shot of a person (typically done with an 85-135mm Full Frame equivalent focal length, or longer) will capture the entire body of a newborn baby and much of their surroundings if shot from the same distance.
This shot was captured with my EF 135mm f/2 L on my 6D (a T4i equivalent lens in terms of mm would be the 85mm) from... I don't know... about 6-8' away
I also cropped it just a tad (not much honestly). Also, I shot it with strong natural light coming in (shot just before 11am) and I was still at ISO5000 and f/2. So, a flash which can be bounced can be HUGELY helpful for indoor pictures, even if you don't decide to use it right away.
Here's another shot with the same lens and camera but after the sun went down that same day. I used bounce flash off the wall in front of her...
Same setup, just added the flash. This shot would not have happened without flash. I would have to be at 25000 ISO or more! lol
So, unless you're wanting some "environmental" shots (which you may and those can be REALLY nice), I'd consider longer focal lengths than 40 and 50mm. Here's a GREAT post about what you can get with wider primes -
http://www.dpreview.com/forums/post/38762824 As you can see from that link, MUCH more thought needs to go into shooting wider shots. But the reward can be ENORMOUS!
2) Once the kids start running around, I see the canon 17-55 /2.8 gets rave reviews, or should I just add an external flash with the kit lens?
I'd say get the external flash anyway. For running kids, I find a fast-focusing prime is GREAT. I bought a LOT of equipment to capture my daughter running around and then slowly whittled it down again over time when I realized that 1) they don't run around like crazy demons for long (her phase lasted about 6 months) and 2) how many "action" shots did I really need? (you get a few and then they all tend to look the same - lol)
In terms of just catching kids moving... it's an eye opening experience. Usually, they're looking down at the ground. Not the best look for pictures. Also, camera AF ability helps and IMO, makes a bigger difference than the lenses. The T4i has the same AF as my prior 60D and I caught a lot of action shots with that camera. It will do well if you learn how to use it properly (learn how to use "back button focusing" and AI Servo with High Speed Continous shooting and shoot in 3+ image bursts to capture "moments" easier). You may find yourself wanting to upgrade to something like the 70D for it's superior AF and FPS (Frames Per Second) ability. Also, if you do, it's live view and more importantly for someone with a new kid, it's video capabilities are definitely better than the T4i. The 18-135 STM you have will pair VERY well with the 70D, should you choose to go down that road later.
3) For taking photos at the hospital, should I look into the 17-55 sooner rather than later? Or would a prime work ok here? Seems that 50mm might be too long. Would prefer not using flash with a newborn.
Well... it depends on what kind of shots you want to take. Are you just wanting images of the baby? Or are you wanting some of mom too? Plus visitors? Etc.? If you just want the baby, as I mentioned above a "longer" lens would be fine. If you want more "environment", wider focal lengths will work best. f/2.8 will definitely be helpful but lighting inside of a hospital isn't really strong, especially in the mother-baby-units. So, you're going to be cranking up your ISO to compensate, even at f/2.8. That's not a bad thing as a noisy picture is still better than no picture. Just be prepared. Black and white conversions tend to look just fine with a lot of noise in them and for such a classic moment, B/W may work really well.
Here's one from the other night I converted...
ISO 12800 - shot with the 6D + 135 at f/4. I cropped quite a bit off as I was standing across the room about 8' away. My (pregnant) wife was reading Kyla her bedtime stories and I thought a moment like this was AWESOME!
As far as using flash... I wouldn't use on-camera flash. It's tiny and harsh. If you're considering flash, I'd get something that bounces like the 430 EX II and angle it behind you and up so that it bounces off of a wall/ceiling corner and REALLY plan your shots so you only have to take one. I don't think flash is a big deal when it's indirect like that. But it's personal preference. If Mom is against it, drop that fight right now

lol
My main area of focus with photography is kids/family/vacation stuff at this time. Thanks!
Your 18-135 will shine for this! Here are some other lenses to consider...
Sigma 30mm f/1.4 ART - it's a little wider than what you're looking at which can be great to capture the surroundings and it's REALLY sharp and really fast/bright
Canon 35mm f/2 (IS or not) - the IS lens is newer with better IQ and obviously, IS. The angle of view will be similar to the Sigma above.
the 40 and 50 you mentioned already
Canon 60mm f/2.8 macro - AWESOME lens and because it's a macro lens, can get ULTRA close. For close up shots (toes, fingers, lips, nose, ear, etc.) you'll want to use it at f/8-f/16 so you'll need a LOT of light for that - bounce flash will be your friend! Take those types of shots when the baby is sleeping. It also performs incredibly well as a portrait lens.
Canon 85mm f/1.8 - this lens was glued to my 60D and then 70D for MONTHS. It focuses extremely quickly and performs very well wide open and slightly stopped down (f/1.8-f/2.5) and great at f/2.8+
So... I know I didn't give you any definitive answers but that's because your shooting style really needs to dictate what you purchase. But hopefully knowing these options and scenarios will be helpful. If you read this and can bounce some info back based on what I've typed here, I (and I'm sure others too) will try and help you narrow things down a bit.