Need info on my grand daughter's EOS Rebel T7 lens dimensions

[showme]

My teen granddaughter recently got a Canon EOS T7 Rebel with an EF518 55mm. She's volunteered to be a photographer for the school newspaper, so my wife and I wanted to get her some lens equipment for Christmas. My wife handled the search and purchase of a lens set that she found on amazon that stated they fit the T7, along with a list of others.

It seems that my granddaughter's camera's lens base is smaller than the one's we ordered. They are 58mm, and as far as I can see, when I measured her camera (she didn't have the manual with her, and wasn't sure where to find the base measurement on her camera), I found it is 50-51mm in diameter, depending if I used the inside diameter (50mm) or estimated the thread depth diameter (51-?). So, after doing a little research, I see there are 50mm lenses, but I'm a little mixed up here, since the box that her camera came in states the zoom lens is 55mm(??). 

What does this 55mm dimension indicate, the lens diameter or the base diameter? And, would her camera's lens base be considered 50mm or 55mm? I really can't see another 5mm of thread depth on top of the 50mm inside diameter of the camera's female lens base receptacle. So, as a no-nothing grandfather of a future photography nut, I'm asking all the experts here (i.e., anyone who knows more than me about these things) for help to figure out exactly what we need to get her. Btw, I realize we could wait until Christmas break is over and have her ask her instructor about it, but she was so disappointed when she found out she wouldn't be able to use it this week, I wanted to find one that fits her camera asap. This is what my wife ordered, and is now being returned. Their bases were too big to screw into the camera.

Thanks for any and all comments and suggestions on this. I appreciate it. Lee

[Commercial link removed per community guidelines and replaced with screenshot to serve as a visual aid.]

[rs-eos]

Any EF mount or EF-S mount can be used with her camera.

Do avoid Amazon though as their are numerous counterfeit, gray market, or just poor quality equipment.

Check to see what lenses are available at Canon’s own online store. There are also refurbished items if reducing cost is needed.

Or, purchase from any of Canon’s authorized resellers. Personally, I rely on B&H Photo.

[rs-eos]

Additionally, it’s only important to understand a few things about lenses. As stated earlier, you’ll need either EF or EF-S mount lenses.

Then, two most important numbers will be the focal length and aperture range. The focal length can also be a range of values.

The other number I think you are seeing is typically on the front of the lens for use with screw-on filters.

[Waddizzle]

The default lens filter thread sizes on the kit lenses in a T7 camera kit is 58mm.  I strongly advise against purchasing the “lens kit” that I see above.  There is no substitute for an actual macro lens or telephoto lens.

Lens filters are not as useful as they once were when all cameras used film.  Digital cameras and digital image processing almost make physical filters obsolete.  I would hold on off on buying accessories that she may not need or even use.

If this is her first camera, then I would advise giving her some time to learn about the basics of photography and the basics of using a DSLR.  Yes, that means there are two learning curves that need to be climbed.

[stevet1]

Lee,

I am a novice myself, so I have to admit I'm a little confused.

I have an 18-55mm lens myself, and I can tell you that it takes a 58mm filter.

The lens mount itself means that you can use any EF or EF-S lens.

I know you meant well, but if I were you, if you can't return the accessories you bought, I'd see if I could trade them in at a site like KEH or MPB and get your granddaughter something like a 50mm prime lens, (worth about $150) and a good sturdy tripod (worth about $125).

If she would like more reach, a 55-250mm IS STM lens runs about $250 and is a good starter telephoto lens. (It also takes a 58mm filter, if she wants things like a color polarizer or neutral density filter.

This will give her time to grow and learn the art.

Steve Thomas

[shadowsports]

Steve's recommendation of an EF-S 55-250mm lens would be an excellent gift.  Her existing 18-55 together with a 55-250 will be a great start for her.  New and refurbished are both out of stock at the Canon store right now.  However, B&H Photo has the 55-250 in stock.  They are an authorized Canon dealer.  

If you have purchased any lens adapters, magnifiers, filters, etc from Amazon, I suggest you pack them up and return them.  They will be low quality junk products (that promise the world) and will actually degrade the quality of her lenses.

If a second lens is out of reach, making a contribution towards a future purchase is always a thoughtful gift.  

[AtticusLake]

Lee: lens mounts, as in how the lens physically attaches to the camera, are not measured in millimetres in today's world.  Instead, they have names, and it's important to match the names.  There's no point in putting a ruler on anything.  Even if some physical dimension did happen to match, there's no guarantee that the data protocol the camera uses to talk to the lens would be compatible.

As others have pointed out, your camera takes EF and EF-S lenses.  That's it.

When you see a lens being advertised as 50mm, or 58mm, or 300mm, or whatever, they're talking about the focal length of the lens.  This has nothing to do with any physical dimension of the lens.  (OK, longer focal length lenses generally are longer.)  You can think of this a bit like magnification -- on the Rebel, a 35mm lens would give you a "standard" field of view; a 70mm would magnify twice as much; etc.  A 58mm is a little telephoto.

Another number you will see quoted -- confusingly, also in mm -- is the filter thread diameter.  This is the diameter of the threaded mount on the FRONT of the lens, which is for attaching filters.  That's important, but it has nothing to do with how your lens attaches to the camera.

If you want a horrendous amunt of information about lens mounts, I wrote an article: https://moonblink.info/MudLake/gear/lenses

[Tintype_18]

I made the mistake of ordering a complete kit online. If I had only known about the Community. I highly suggest that you download the manual, have the camera in hand and start with some of the basics. The manual is over 300 pages so there is a lot of information that would be hard to digest in a few sittings. I also like the idea of a DSLR as you can experiment and not waste film as in the olden days. Above all, heed the advice of the community members. The community has a trainload of information, expertise, experience and a genuine desire to help newbies. Oh yes, make sure you always have an extra charged battery; Murphy's Law- Your battery will fizzle in the middle of a shoot.

[showme]

Well, thank you very much, everyone! This is, obviously, my first post on here and I was pleasantly surprised to find all these replies this morning. The answers that you all provided were just what I was looking for. I was really confused about the numbers I was seeing. (I was pretty proud of myself for having an old metric tape measure from a job building a federal court house in St. Louis [retired Ironworker], although I didn't know exactly what I was doing with the numbers after that. I had to laugh at myself after reading your replies. I'm reminded of an old movie with Nick Nolte and Debra Winger titled "Cannery Row". In one scene of that movie, a group of local homeless men that have befriended Nolte's character, who is a marine biologist, have chipped in to buy him what they believe is an excellent gift to help his studies of octopi (octopus-es)- a microscope. They are all overjoyed about their find, and E. Emmet Walsh, the groups leader, excitedly unveils the gift and exclaims "A new...Microscope!", which turns out to be a telescope on a tripod, only with the lens facing down with the eyepiece sticking up in the air. He adds, happily sharing that "It was the biggest one in the catalogue!!", not knowing the difference between a microscope and a telescope. This is me with cameras. So, thank you all for clearing me up on what it is I'm looking for. 

I love my wife, but sometimes she just doesn't do her research when she looks for gifts, especially for our grandkids. I told her no more aftermarket stuff for Kate's camera (or anyone else's). I've looked at a few Canon lenses, and with the information I've received here, I'm a little more confident about what we need to find. And as a few of you have stated, buying aftermarket equipment is a problem waiting to happen, which could turn into a problem and possibly a public embarrassment to our granddaughter. As a retired Ironworker of 30 years, I found out a long time ago that the tools I used every day could cause an injury or even kill me if they failed me a hundred feet in the air. My purchase of high quality hand tools (Klein, Armstrong, White) irritated her at first, but after she saw me in the air one day standing on a spud wrench stuck in a column's bolt hole, she realized that a failure of a tool could be fatal, she never complained again. Anyway, thank you all for the help, and I will try to remember to report back here when we figure out what we choose for Kate. And don't be surprised if you start seeing a new member on here, after I tell my junior high aged grandaughter about this forum. She'll be happy to find there's a place she can come for help. Thank you all again for educating an old geezer. I'll be passing this along to Kate, and hoping she goes far in her journey into photography. Lee Butcher

[johnrmoyer]

In addition to the good information others have provided, I hope some of this might be helpful.

You can get the manual for that camera at: https://www.usa.canon.com/support/p/eos-rebel-t7 ( 326 page PDF  ) Page 278 of the manual lists some of the accessories that will work with the camera.

Lenses (at various cost level) that I enjoyed using with a similar camera include:

EF-S24mm f/2.8 STM for closeups https://www.usa.canon.com/shop/p/ef-s-24mm-f-2-8-stm       

https://www.usa.canon.com/shop/p/ef-s-55-250mm-f-4-5-6-is-stm   as others have mentioned.

EF-S18-135mm f/3.5-5.6 IS USM is similar to the 18-55mm, but with better autofocus and a wider range of focal lengths.  https://www.usa.canon.com/shop/p/ef-s-18-135mm-f-3-5-5-6-is-usm    .        

For more information about focal length and how it is used by photographers: https://www.cambridgeincolour.com/tutorials/camera-lenses.htm.  

https://snapshot.canon-asia.com/article/eng/lens-faq-what-is-focal-length   what is focal length