seahawk505 Loc: Albuquerque, New Mexico

New to UHH. My original "real" camera was a Canon film body, with kit lenses, after which I bought the Rebel Xs and used it happily for several years. More recently,I have been shooting with a Panasonic Lumix FZ47, which is great for traveling. I travel a lot, and shoot landscapes, people candids, some flower closeups. I have been doing (way too much) reading on what's out there today, and have pretty much settled on upgrading to Canon 70D. Currently, Sam's Club has a kit deal that includes the 70D, with an 18-55 IS STM and 55-250 US USM, and I'm about ready to go for it. What am I missing?

MT Shooter Loc: Montana

Since you have already been using the Rebel Xs, you are already aware of the shortcomings of the kit lenses, although the newer STM models are of better quality. If you do get that kit, I might recommend you look for a better quality lens to replace the both of the plastic mount kit lenses and then sell them off to recover the cost of the new lens. The nice thing about the package deals is that the discount is always enough to allow selling the lenses for more than you actually paid for them when compared to the cost of getting a body only.
Good luck.

rehess Loc: South Bend, Indiana, USA

Other than durability, what issues do you attribute to plastic mounts??

MT Shooter Loc: Montana

That's pretty much it for the mounts. They are easily broken and wear prematurely (once they get so loose you can get intermittent camera/lens communication problems). Much less durable than standard chrome plated brass mounts.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

I think that is a very astute response, but doesn't it depend on the level of use and lens changing?

What may be a problem for the more serious user, may not be problem for a more casual user.

Is it possible to put some metrics around this for guidance?

MT Shooter Loc: Montana

That's exactly why the manufacturers do not make any upscale lenses with plastic mounts, only the basic, entry level lenses are offered that way.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

Agreed, but how do people identify what they need?

What frequency / how many lens swaps happen before there is a potential problem?

All my current lenses are metal mounts, my earlier lenses with plastic mounts are with my wife. Her level of usage and changing lenses is much lower so I think they will never become a problem in pragmatic terms.

You are in a position to provide an informed perspective beyond a high level but unspecified statement.

Can you add some specificity to the statement about amount of wear?

MT Shooter Loc: Montana

Not sure what "specificity" you are expecting. The simple facts are that the contact pins in the Canon body are 0.11 mm wide at the base and taper to 0.06mm wide at the tip. The contacts in the lens are 0.14mm wide and are flat. So the camera pin uses 43% of the lens contact for full communication. Assuming the pin is exactly centered on the flat leaves 0.04 mm of play for the lens mount. So if you get 0.05 mm play in that plastic mount you will lose communication on one or more of the contacts. But, we all know that these products are mass produced in large quantities and the tolerance is subject to the assembly process. I would have to assume that the 0.04mm leeway for the contact pin is more likely 0.02 mm actual allowable movement. With 8 contact pins in the assembly you stand a very high likelihood of loosing communication contact as the plastic mount on the lens wears. Since all body mounts are metal, its clearly the plastic lens mount that will receive the wear of repeated couplings and un-couplings of the lens. Exactly how careful a user is, and how often they change the lenses will obviously be a determining factor in the amount of wear received, as well as to the timetable of that wear reaching a point of possible loss of contacts between the pins and the flats.
This is not exclusively a Canon problem as every one of the camera manufacturers has a certain inventory of lenses that they use plastic lensmounts on, its purely a cost-saving measure.
When your lens is mounted on your body and locked in place, hold the lens tight and turn it back and forth to see exactly how much play you already have in the mount. All lenses will show a slight amount of movement, more expensive lenses will show less overall, and brand new lenses will have less play that older lenses.
Plastic is just a fact of life in the world we live in these days. Everyone has to learn to live with its shortcomings as they benefit from its lower cost, and lower weight as well.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

Which is all good stuff, but doesn't really give actionable guidance to the casual user.

How many times can I change a lens with a plastic mount before it may become an issue?

20times? 100 times? 1,000 times? 10,000 times?

What are the numbers for lenses with metal mounts?

Are there any MTBF numbers?

I remember when people made the same argument about canon switching from the breach lock FL/FD lenses to the bayonet FDn lenses. Never heard much evidence to really support the logical argument.

I do not disagree with the logic, but some guidance on light use vs heavy use would be helpful if you understand my point.

MT Shooter Loc: Montana

Then I suggest you take the time to sit and install and remove a plastic mount lens thousands of times and calibrate the wear over the course of the experiment. As far as I know no one has ever wasted that much time to actually find out the exact number at which the failure is noticeable.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

So, at the end of the day, there is no real guidance that you, or I can stand behind other than to say we think plastic wears faster.

I do not mean this in a negative way, you give some of the best, most valuable and balanced guidance on the forum in my opinion, but it seems we don't really have an answer in every day layman's terms.

So, for light use, plastic is fine, for heavy use metal is better.

So if you change lenses say 200 times a year plastic maybe OK, over say 5 to ten years, but if you change lenses 200 times a week, don't even consider plastic?

What can we say in those kinds of terms?

Come on, it isn't really that hard to put a stake in the ground for others to comment on. Wait, I have much less experience than you do, and I've just stuck a straw horse out there to kick around.

I've made my own decisions, but I think we can't always justify the plastic is bad argument unless we put some "meaningful" evidence behind it.

For example, I liked the comment another member made recently:

"Using a Honda Fit to tow an RV isn't a good idea", or similar.

Doesn't mean that a Honda Fit is a bad vehicle, but there are use cases that it isn't designed for.

Please take this as a request for interpretation of your excellent advice, and not challenging any detail that you have posted.

rehess Loc: South Bend, Indiana, USA

At another discussion forum devoted to photography, I've encountered guys who are absolutely certain that the use of plastics should be limited in constructing camera bodies; they point with disdain at Canon and Nikon, who seem to use virtually no metal. When I've asked for details about actual problems with those bodies, I've been told that it just stands to reason that stronger material should be used. I'm hearing the same "logic" here.

Yes, the most expensive lenses use metal mounts, but Canon also colors them white, and some companies put gold stripes or other distinctive markings on them. How do we know for sure that certain characteristics are for performance as opposed to being a marketing ploy?

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

Once again, not wishing to disparage, just seeking clarification, if the flange is metal, but is mounted into a plastic lens body, it may reduce wear, but does it deliver enough structural integrity for any given lens?

Something tells me it isn't as simple as plastic lens mount means bad, metal lens mount/flange means good.

klbuild Loc: Durham, north carolina

Bought this kit at Costco about 7 months ago and love it. I think you will as well

Billyspad Loc: The Philippines

What your missing my man is the advice you came here for. Instead the post has been hijacked by people talking complete jack shite about things they know little of and are even less qualified to comment on. So yea a compny like Canon makes plastic mounts that are not fit for purpose? Geez they just love the sound of their own voices.
So talk with me cos i got brain cells that work. You are in my opinion buying he best camera available for the price and it will suit all the requirements of 99% of casual to heavy uses. Its the kit I would buy tomorrow if I had funds but would add a 10-20mm wide angle lens to it. In fact for what I take i would rather that than the 55-250. Go and buy it enjoy it and for Gods sake do not listen to some of the assorted numpties who drone on in these forums.