08-25-2017 05:39 PM
The T6 is more of a replacement for a T3, than an upgrade. I would advise against that path.
What is it about the T3 that causes you to think that you need an upgrade? What features are you looking for in a new body?
08-27-2017 01:41 AM
I agree with kvbarkley. You selected a lens that is well above the IQ level of your Rebel. It is intended to be used on a FF body but it will work very well on the crop sensor cameras. It acts like a 135mm lens on a FF. The Siggy 85mil f1.4 is one of the sharpest 85's made. Maybe the sharpest.
It is usually best to keep your gear more or less equal. Staying in the crop sensor world the 7D Mk II and the Siggy would be fantastic together. There are things other than IQ that a camera like the 7D Mk II can offer. Especially with that lens attached.
08-27-2017 12:07 PM
In a word, it isn't. But besides sensor technology increasing the supporting electronics also get better. The big myth is the best IQ comes from the best sensor. Of course the sensor is very important but it isn't the only part to consider. When judging a camera all its params must be considered. When you add a lens it must also be considered in the equation. Make sense?
This is where the misconception that FF is always better than crop. And, that simply isn't true.
08-27-2017 12:19 PM
Considering IQ only, not features, why would a CR2 file from a late model Rebel be inferior to any other APS-C camera in the Canon line?
Any number of reasons. Different APS-C cameras have different sensors, different built-in computer chips, different autofocus systems. more accurate lens alignment, etc., etc.
And in any case, the "features" of a camera are what they are. You can't necessarily separate them from their effect on image quality.
08-28-2017 11:24 AM
The T6 is very similar to the T3, except for two major things. It has better focusing and a newer processor. If that is worth it to you then go for it. The T3's processor and focusing worked great yesterday, they'll work fine tomorrow. With the Sigma 85mm you'll get good shots with either.
I have a T5 as a back up which is almost identical to the T3. It's nice and I like it. If you were moving up then I would recommend the T7i or even an 80D. (I use an 80D, my wife uses a T6i, and a good friend uses a T3) The T3 is too similar to the T6 in my opinion. It would almost be like getting a newer same old same old. If you don't want to take a step up, then by all means, stay with what you have. The T3 is still a good camera. If your T3 has a lot of shots on it though or is acting a little quirky, you might start thinking of replacing or stepping up.
The T7i is around $750 and the T6i $700. If the added benefits of the T7i are worth it, then spend the extra for the newer camera. (There are some bargans for both out there for a lot less, but be cautious.) NOTE: the T6 and T6i are not the same camera. The T6 is entry level and the T6i is a step up. The difference is similar to a sub-compact vs a compact car.
The 77D is around $850 and is an advanced T7i. The difference is it has a LCD display on top and the selection knob on the left, similar to the more expensive Canon models)
The 80D is around $1,100, but is about due for an update. An update will drop the price on the 80D or entice you with nicer features.