Instruction: Given a question and the related document, and generate the answer to the question based on the information provided in the document.

Input:
Question: Is this lens compatible with the Canon 70d?  I keep seeing conflicting reviews.. I really want this lens!
Document: This is the lens that I always keep on my camera by default. It zooms out a good amount and in and is the perfect all in one lens. I use it mostly for DSLR video  shoots and this is great for interviews! It is very clear and does decent in low light. Highly recommended if you want the professional look but can't afford the Canon!
I purchased this lens because I wanted a faster lens with a decent zoom range but did not want to spend $1,200. After reading many great reviews on this lens I bought it. So far I am very impressed. Auto focus is quick and accurate, not loud either. Pictures look very sharp and accurate. It is kind of a large and somewhat heavy lens but that really doesn't bother me.
I wasn't sure how I would feel at first about this lens the lens hood felt a little cheap and plasticy but after using it I really like it. I have always used Sigma and Canon lenses so this is my first Tamron. I bought this to be compatible with my new Canon 6D. Takes some great macro even though I wish had much longer telephoto. So far so good :)
In addition, my Canon 430exII flash does not do as good a job with this lens as with all the Canon Lenses. The pictures are a little too dark.I'm happy with the Tamron and consider it an improvement over the 18-55 mm kit lens but it's not quite at the Canon L level. I've taken some really sharp pictures with the Tamron and it will be the lens I keep on my camera. However, if I'm shooting indoors and need to use a flash I will use my Kit lens.
I purchased this lens because of its highly positive reviews and to replace or implement the kit lens that came with my Canon Rebel XT. The lens is a good performer, especially in low light, but if you're satisfied with the kit lens on your Rebel, you may want to use that lens for awhile before making the move to a more expensive lens. The Tamron, while sigificantly better in build quality and features, is not an extreme improvement over the kit lens in my opinion.
I don't normally write many reviews for the products that I have purchased but I had to write about this lens. I am a photographer and like most who have reviewed this lens, I didn't want to drop the money for the Canon L lenses just yet. I have been reading the reviews on this lens for months and for some reason it kept calling me back. So after months of speculation, I went ahead and took the chance on this lens... and man, am I glad I did!
I had high hopes reading the reviews for this lens and was not disappointed. My first portrait session with this lens resulted in simply beautiful shots. I am semi-pro and limited by my small budget. I can't afford the Canon L series lenses at this point but the experience I've had with this lens so far does not make me feel like I'm suffering because I couldn't afford the higher end Canon lenses. If you want professional quality at a fraction of the cost this lens is for you.
I didn't want to pay over $1000 for the Canon EF 24-70 f2.8L. I can appreciate the quality of Canon L lenses. I have the 300 f4L IS & 70-200 f4L. I found many favorable reviews for this Tamron. I also found some reviews relating to focus issues. For 1/3 the price of the Canon, I decided to take a chance.The first thing I did when I received the lens was to perform a focus test.
My Canon 28-70 lens was just the opposite - a quick transition to out-of-focus towards the camera but the background stayed very much in focus. WOW that is interesting. Because if I am shooting someone at mid range I DO want the background to go out-of-focus as fast as possible, and I don't really care about the foreground, so for me, the Tamron is better.Has anyone else noticed this?
Well with these criteria in mind, I started to really look at the Canon 24-70 f/2.8L. This lens has received epic reviews from every photographer. Its built quality and its pictures are perplexingly amazing. My versatility requirement has been met at every angle.
Answer: Tamron told me there is a firmware update that must be installed to work well with the 70D.  It was just developed about two months ago.  Any lenses made before then will need the update installed.  I just sent me lens to Tamron this week for them to update it.  Up to this point I could only take a handful of pictures at a time before it brought up an error message telling me to clean the contacts on the lens or camera (can't remember the exact wording).  I'm hoping all is well when I get the lens back this week.