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6d w/ 105mm how far can I "zoom" in for pseudo 300mm shots?


I've just ordered my first dslr, a 6d with the 24-105 L lens. I've had digital point and shoots before but my last SLR was a film camera so I'm unsure of the IQ of a nice dslr.


I generally use a 300mm lens a lot, but since I just dropped almost $2800 dollars on this new setup, I really don't want to spend another grand (at least) on a longer L lens at this time. Thing is, I'm going on a nice vacation in a couple of weeks and I know that I'll be missing a longer lens.


So I thought that maybe if I just shoot with the 105 focused to "infinity" and then crop and zoom in on the finished image, I could have the effect of a longer lens without actually having the longer lens. Will that actually work? Will the image quality be good enough for that to work? Will the images be sharp and focused with this technique? I know there are a lot of variables such as available light, ISO, etc. I don't plan to blow any of these photos up very large--most of them will be snapshots on the computer but if I take some really exceptional ones they could become wall art.


Or is this a dumb idea and I should buy a longer lens?

Which leads to part 2:

If I should buy a longer lens, having never show with an L lens before and hearing that they're awesome, would I be really disappointed if I got a non-L longer lens. Would I see a ton of difference in IQ, given that nearly all will be seen just on the computer and maybe only a few blown up larger?


I also thought about maybe getting an extender as a less expensive option but they don't list this lens as being compatible.


I know this is a bit long winded but thanks for any help you can offer!



Maybe I don't know something I should, but I don't know why you would focus to infinity just to help with the zoom. 


All you should have to do is shoot like you normally would all the way out at 105mm and simply crop the photo later on...the 6D has plenty of resolution for that.

I'm an advanced amateur, am not the average point-and-shoot photographer out there, and am willing to take any critique or advice that will improve my photography.

Yeah I guess "focus to infinity" didn't really need to be said. 🙂 I was just thinking that if something I wanted to shoot was far away and not really that large in the 105, that it would be focused to infinity anyway. But you're correct, I'd just focus on it normally and blow it up.


Thanks also for the comment about the 6d having enough resolution for blowing up. That's what I was hoping I'd hear!


I'm glad you figured it out. Just make sure that if you are going to crop a certain picture quite a bit on a specific area...make sure you have the focus right on, because when you crop that much and even blow it up, you'll be able to tell if you messed up.


Also, if you really would like to have an "L" telephoto, but don't have money to buy one, I suggest considering renting one. You'll be surprised at how cheap it is to rent professional, top quality equipment at a fairly cheap price.


Check out:

I'm an advanced amateur, am not the average point-and-shoot photographer out there, and am willing to take any critique or advice that will improve my photography.

If rental is an option then the EF 70-300mm f/4-5.6L IS USM is pretty compelling, especially for travel due to it's relatively short actual length.



Brian - Canon specialist trainer, author and photographer

The 70-300 is actually the one I was considering. Didn't look into the specs that much but good to know it's a good choice for travel

I think you'll be very happy with your purchase, but if I were going on a major trip I'd want a 70-300 with me too. The Canon 70-300 IS gets very good reviews & has been on sale here in Canada for about what used ones sell for so you might want to consider researching it. As for focusing you really won't need to do that because the AF should pretty much nail it in most circumstances, and the IS on the 24-105 works really well, BUT remember to turn it off for panning shots.

Based on some shots that I took when I owned a 5D mark 2 using the 24-105 L IS you can do some heavy cropping for on screen use but I don't know how deep I could have gone & still printed 8 X 10's, but I'd say you could give up about 1/2 the file & still get a decent print. I have a lens samples album on line with a couple of shots that you could download & play with from that combo & with the 6D almost having the same Mpixels they should help in whether or not you think you'll need a longer second lens for the trip.

This is a VERY deep crop of the first real world shot I took with the 5D2. I did however do a few test shots around home because I bought it just in time for my annual vacation. avatar.jpg


The full file can be found here, and using the right arrow will take you to a couple of others that can be downloaded. to download use the Actions > Download photo tab.



"A skill is developed through constant practice with a passion to improve, not bought."

 cicopo thanks that's a really good illustration of how much you can zoom/crop in. The crops don't look super super sharp, but certainly better than I thought they might look. 
I'm leaning towards getting this lens:
It's 1/3 the price of the L series (and I've seen it for mid $300 used) and seems to be pretty decent lens for the money.

Glad to be of help & that's the lens I was suggesting. I've owned the 70-300 DO (much more $$$) and although my copy was very good most suggest the less expensive IS version is very close in Image quality. Even if you want to upgrade later to something better just having it for the trip (if bought right) & sold once it's over seems a logical way to go. At least 1/2 of the equipment I use was bought used (usually face to face) & in the case of lenses they still are worth what I paid for them after considerable use.

"A skill is developed through constant practice with a passion to improve, not bought."

I really don't recommend that lens over other ones. It's a decent lens, but Tamron's 70-300 VC is a little better in terms of sharpness and it also has full time manual focusing(the canon does not). It is about $200 cheaper for that slightly better quality.
I'm an advanced amateur, am not the average point-and-shoot photographer out there, and am willing to take any critique or advice that will improve my photography.
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