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

[Brad]

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!

[Brad]

I went ahead and ordered that EF 70-300mm f/4-5.6 IS USM from canon refurb. It should arrive in two days.

I don't think my crop to zoom idea would work that well. With my 24-105mm L lens, I've taken a few hundred shots now in a variety of situations and subjects and looked at various image qualities/sizes from full raw 20mb, mraw 11mb, jpeg L 20mb, and jpeg M 8.9mb and none of them are very sharp when zoomed in to 100%.

In fact I'm quite shocked at how unsharp and unfocused they all look at 100%. It seems like they're not even as sharp as my canon s100 point and shoot is. From a "fit to screen" look on my 17" monitor they look ok, but they're sure not that impressive when zoomed into 100%.

Given that the 6D is my first dslr, maybe my expectations were too high--but I was really expecting laser sharp focus and sharpness even at 100% zoom. Is that unrealistic? Not that I'm going to blow them up to giant proportions anyway (most will just reside as snapshots on my computer) but I was expecting to really be able to blow up to 16x24 or 20x30 if I found a shot that warranted it. Maybe I'm getting some distorted view of reality though by looking at my monitor with its 72dpi resolution? Just a bit underwhelmed by the camera so far unfortunately.

[jfo]

Could you post some examples along with the exposure settings?  Maybe its the shooting conditions and/or the camera settings.

[cicopo]

Now that you have it you have to learn how to hold it properly & you need to be sure you have decent shutter speeds for the situation. You also need to learn how to set it up to match what you like re output if shooting jpg's or how to process the RAW files including how to sharpen them. You also need to learn that as the resolution goes up so does the effect of very minor shake. With higher resolution seensors what would have been a 1 or 2 pixel smear is now 5 or 6 & maybe a 7 pixel smear. Viewing at 100% is nice but the reality is that 50% is supposed to be the maximum at which these things should be judged.

[Brad]

"Now that you have it you have to learn how to hold it properly & you need to be sure you have decent shutter speeds for the situation. You also need to learn how to set it up to match what you like re output if shooting jpg's or how to process the RAW files including how to sharpen them. You also need to learn that as the resolution goes up so does the effect of very minor shake. With higher resolution seensors what would have been a 1 or 2 pixel smear is now 5 or 6 & maybe a 7 pixel smear. Viewing at 100% is nice but the reality is that 50% is supposed to be the maximum at which these things should be judged."

That's part of what I'm trying to figure out--the camera's limitations and what are realistic expectations.

I think I'm holding and shooting fine--I've been shooting SLR for nearly 30 years ...film, that is for SLR-- my digitals have all been point and shoot until now.

Shutter speeds--well if I'm shooting on auto mode then I think it should choose the shutter speed correctly. I've shot on all modes of the camera--all of the differnt programs, tv,av, p, ca, a+, etc. and I'm getting similar results. I shot a dozen or more last night in the house on a tripod with the delayed shutter to eliminate any hand shake and got similar results.

Outputs may be where I need some help...this is my first time shooting in raw and I've heard people say that they often don't look that good and maybe that's the issue. I have played with the canon DPP program a bit but I haven't gotten deep into them. I can tell the the colors and sharpness of the same jpeg image often does look better so maybe it's just a question of me knowing what I should expect.  And maybe I should only be viewing at 50% if that's the way to look at it then the images obviously do look a lot better. But again, Raw and a Dslr is new to me so I'm trying to figure it all out before I leave for Japan in 5 days.

Thanks for your input guys. I'll post a few shots later today and maybe you can let me know what you think.

[cicopo]

What ISO are you using? You may want to see how high you can go before seeing noise. It may surprise you what it can do. As for comparing it to film unless you had a darkroom you NEVER blew up the negatives in the same way you do a digital file which is why we don't do a fair comparison. If you did do some darkroom work think of the comparison of 100% on screen to using that little magnifer we set on the print easel to fine tune the enlarger to paper focus before actually putting paper onto the easel. Also remember that you're likely sitting relatively close to your monitor but if you print 16 X 20 or 20 X 30 you'll view it from much further back. One other thing many don't consider is the quality of their monitor & it's brightness setting. Serious editing requires an IPS panel for accurate color reproduction & in general the brightness will be below 25%. I use a Dell 24 inch monitor & with the brightness set at 20% what I see on screen (brightness & colors) matches my printers as accurately as my eyes can detect. 

http://en.wikipedia.org/wiki/IPS_panel

[Brad]

Ok here are a few photos. I didn't take any of them with any artistic intent at all...just trying to get a feel for the camera's output and capabilities and how I need to shoot moving forward.

General info -- 6D with 24-105L lens. IS on. Mraw or raw. Mostly hand held but the christmas ones are on a tripod with a 2 second timer delay to eliminate shake.

tree bark - mraw (11mb), 1/60, f4, 1250 ISO, full zoom on 24-105 L, 100% blowup

truck - mraw (11mb), 1/250, f5.6, 100 ISO, full zoom on 24-105 L, 100% blowup

wall - mraw (11mb), 1/160, f7.1, 100 ISO, full zoom on 24-105 L, 100% blowup

christmas - full raw (24mb), 1/30, f4, 400 ISO, full wide on 24-105 L, 100% blowup, on tripod and 2 second shutter delay to eliminate shake

These are just a few examples but they reperesent what I've seen from a couple hundred shots now. With the exception of the truck, nothing else looks very sharp to me. It seems to me that nothing is very sharp unless there's a lot of light, more specifically sunlight, because in the christmas shot it was fairly bright in the house even though it was evening. I'd say there was a good 800-1000 watts of lights on in the room.

So what do you guys think? Am I missing something here or are my expectations just too high? And yes, I realize that in the real world I won't be blowing these up to 100% prints, but it just seems to me that if the fine detail is not that good then the larger photo that those fine details make up won't be that good either.

Thank for any advice or clarification!

[cicopo]

Those don't look right but with all the variables of being new to RAW plus only being able to process in DPP could you please try large fine jpg & use the base setting for a few & then increase the sharpenning setting 1 or 2 positions to see what you get. If they don't improve I'd recommend doing a micro adjust on the lens & try again after that.

If you're limited to indoors see if you can get a decent shutter speed by increasing the ISO to 3200 for the test.

[cicopo]

One more thing to suspect. DID you buy a UV lens filter? If so take it off & re test. Lots & lots of complaints re filters causing softness. .

[Brad]

I have a uv filter but it wasn't on the lens on those shots.

I've been shooting everything in raw and jpeg. Here are the same shots in jpeg. The christmas, truck, and tree ones are large fine jpeg (20mb), the wall is medium fine (8.9mb).

What do you think? They don't look that sharp to me even in jpeg. Actually the truck one looks pretty good as it did in raw. Regarding lens microadjustments...the 6d is supposed to read the lens and make adjustments to the image based on the lens. Maybe that's just to take out the general design imperfections of each lens and doesn't do what you're suggesting. I'm not sure.

I should be getting the 70-300 delivered tomorrow and will take some shots outside if it's not raining. That might indicate if it's an issue with this 24-105 lens or the camera itself.

Thanks again for your help!

[Brad]

Wasn't sure what you meant here "If you're limited to indoors see if you can get a decent shutter speed by increasing the ISO to 3200 for the test."

You mean to increase the ISO to get faster shutter speed shot to eliminate the possibility of camera shake? That's a possibility of course, but as I mentioned the christmas shot was taken on a tripod with 2 second delay to eliminate that possibility.

Here's a 100% crop of a waterfall I took the other day. It was an overcast day--jpeg medium fine, f4, 1/2500, ISO 6400. Maybe this is the type of shot you wanted to see?

I'm starting to wonder if it might also be that the AF can't focus well on less well lit shots? Maybe those shots are just slightly out of focus even though the camera thought it was locked on. I'm thinking that since the shot of that truck in the sun seems to be the best quality of all--vastly different than over 100 other shots I took under cloudy skies, in the shade, or indoors in the evening. Just a thought.