A question for Canon 7D owners (mainly)

[LongQ]

Now the 7D has been around for a while I assume there is a body of practical use observations that people can consider when asked about performance, etc.

I've been reading about the Mk2 EOS 70-200 f2.8 lens which seems to produce some superb results albeit at twice the price of the Mk 1. Many are suggesting that - with the larger pixel count sensors these days, the 7D being a case in point for the crop sensor bodies - the lens is good enough to be considered for use up to the 400mm range mark because one can crop severely and still have a reasonable pixel count and image size for most purposes. If you start with 18Mp and halve it, especially with incoming lighting from the centre of a lens, it should still be a great image with plenty of potential for processing.

How does that stack up in practice? I'm assuming it needs to be considered on the basis of using L spec lenses in general, not just the 70-200 II, although the specific point may be most appropriate for that lens.

Edited by LongQ on Monday 23 August 16:36

[minky monkey]

I've got a 7D and the ability to crop into an image is mightily impressive.

However, it's got to be a pin sharp image to start with. What I do notice, is that you really do need a good technique to be able to take advantage of the MP's. You've also got to have good glass upfront, I really notice the difference in quality when cropping a shot from my cheaper walkabout lens.

[Ledaig]

LongQ said:

I've been reading about the Mk2 EOS 70-200 f2.8 lens which seems to produce some superb results albeit at twice the price of the Mk 1. Many are suggesting that t=with the larger sensors these days - the 7D being a case in point for the crop sensor bodies - the lens is good enough to be considered for use up to the 400mm range mark because one can crop severely and still have a reasonable pixel count and image size for most purposes. If you start with 18Mp and halve it,.......

Not saying you wouldn't manage to obtain good images, but...if you are going from 200mm to 400mm via cropping, you will have one quarter of your original number of pixels - not half.



Which also helps explain why megapixel branding these days is nothing more than marketing bull, if you want to double the resolution of a 10mp camera for example, you need a sensor of 40mp.
Jumping from 10mp cameras to 12mp, 14mp etc will not actually net you much of an increase.

[LongQ]

Ledaig said:

LongQ said:

I've been reading about the Mk2 EOS 70-200 f2.8 lens which seems to produce some superb results albeit at twice the price of the Mk 1. Many are suggesting that t=with the larger sensors these days - the 7D being a case in point for the crop sensor bodies - the lens is good enough to be considered for use up to the 400mm range mark because one can crop severely and still have a reasonable pixel count and image size for most purposes. If you start with 18Mp and halve it,.......

Not saying you wouldn't manage to obtain good images, but...if you are going from 200mm to 400mm via cropping, you will have one quarter of your original number of pixels - not half.



Which also helps explain why megapixel branding these days is nothing more than marketing bull, if you want to double the resolution of a 10mp camera for example, you need a sensor of 40mp.
Jumping from 10mp cameras to 12mp, 14mp etc will not actually net you much of an increase.

400mm would be at the extreme end of usage range. I would be more likely to be operating in the 300mm region and below and thus the 'half' would be a target for comparison. Of course it all depends on how big one wants of display/print. But that aside I take your point. At the 70 end things would be like for like with my current lens so one would assume that there would be an improvement of some sort given the reputation of the 70-200 Mk2. (Though my current 70-300 DO is by no means poor so most of the expected image quality benefit would have to come from the improved sensor.)

The thing is that much has been written about 'improved' resolving power in addition to the pixel count increase. Now as one who, when conditions and 'good light' combine well, is quite happy for many purposes (especially web posting needs) with the results that some oldish 5 and 6Mp pocket cameras can produce (horses for courses) I agree with you about pixel counts. Depending on the subject and the purpose a 6Mp image cropped to about 1/6th of the original size can still produce a reasonable screen view or even print up to a little under A4 size. Not bad for something that only cost a couple of hundred quid to start with. Of course the hit rate for getting such images from lowly hardware is somewhat compromised compared to the middle range dSLR hardware. In some situations the same sort of results are simply not possible - but that does not negate the pixel coun argument you put forward.

[LongQ]

minky monkey said:

I've got a 7D and the ability to crop into an image is mightily impressive.

However, it's got to be a pin sharp image to start with. What I do notice, is that you really do need a good technique to be able to take advantage of the MP's. You've also got to have good glass upfront, I really notice the difference in quality when cropping a shot from my cheaper walkabout lens.

Interesting.

I have seem the same point made elsewhere about starting with a top quality image. It makes sense, though I have been quite impressed with sample images produced by unknown techniques. Presumably the techniques were at least adequate!

One thought that occurred to me was that one might not see a great benefit for action shots, no matter what the glass quality, unless using a high shutter speed. Indeed I have even read suggestions that perceived sharpness might be worse. Any thoughts about that suggestion from your experiences?

[minky monkey]

For me, you need the sharpness (to a degree) to be able to maintain the detail when you crop in really tight.

If there's any blur (poor focussing or too slow a shutter speed), the tighter you crop, the more you notice it to the point where you bin the shot.

If you can't get that detail to start with, you're never going to be able to crop tightly. I shoot a fair bit of football, I use the cropping ability to aid me as I've only got a 70-200 F4 IS L so it gives me a bit of assistance.

Edited by minky monkey on Monday 23 August 18:18

[LongQ]

minky monkey said:

For me, you need the sharpness (to a degree) to be able to maintain the detail when you crop in really tight.

If there's any blur (poor focussing or too slow a shutter speed), the tighter you crop, the more you notice it to the point where you bin the shot.

If you can't get that detail to start with, you're never going to be able to crop tightly. I shoot a fair bit of football, I use the cropping ability to aid me as I've only got a 70-200 F4 IS L so it gives me a bit of assistance.

Edited by minky monkey on Monday 23 August 18:18

OK, so you are taking action shots and cropping from the good lens to get results you are happy with. What sort of shutter speeds do you need to use to get that happy feeling? Indeed do the shutter speeds matter that much or is it more a case of when a shot works it works and if you take enough, enough will work?

I'm not suggesting that you need to blitz with the 8fps to get results, more a question of how many shots turn out acceptably sharp for cropping purposes given the variables of moving targets.

My thinking. For head on action I tend to use a fast shutter speed so sharpness, all things being equal, should not be a problem in most cases. However for panning a fast moving subject it will be. Pixel perfect panning probably only occurs by chance no matter how much practice one has. Usually 'damn close' is close enough. But I could see the potential for close to look awful for a very critical sensor. Misplaced concern or something worthy of discussion?

[Ledaig]

LongQ said:

400mm would be at the extreme end of usage range.............

I agree with what you say, I was just clarifying the half 'mp' point.

Trust me, if I thought pixels were that important I would be using a D3x and not a D200/D3 combo.

[LongQ]

Ledaig said:

LongQ said:

400mm would be at the extreme end of usage range.............

I agree with what you say, I was just clarifying the half 'mp' point.

Trust me, if I thought pixels were that important I would be using a D3x and not a D200/D3 combo.

And you are right to do so - I was thinking practically rather than considering the proper numbers.

The raw theory suggests that all should be well but the practical results may not offer much.

If all I would get is pretty much the same as a 10Mp sensor with a 70-300 lens but some added camera features, then the cost comparison does not look great. Cost so far £700. 7D body, lens, upgraded memory capacity - £3,200 at best. Uk prices, approx.

Hmm.

I have little doubt the combination would be better - but would it be £3,200 better?

[pernod]

My 2c worth, just to suggest a totally different approach to this problem...

In my winnie-the-pooh brain I'd say the biggest advantage of the 7D if you are looking for extra reach is actually a mix of resolution and it's exceptional ISO performance from a crop body.

Assuming it is reasonable shooting conditions, the ISO performance is more than enough to offset the reduced light from using a teleconverter. While these are known not to give L-sharp images, the extra MP of the 7D means you can down-sample the image to increase its apparent sharpness and still have a large enough image to play with.

I've never actually used a teleconverter on my 7D to test this, but I have down-sampled a few images to increase sharpness with reasonable results.

[RobDickinson]

minky monkey said:

I've got a 7D and the ability to crop into an image is mightily impressive.

However, it's got to be a pin sharp image to start with. What I do notice, is that you really do need a good technique to be able to take advantage of the MP's. You've also got to have good glass upfront, I really notice the difference in quality when cropping a shot from my cheaper walkabout lens.

Same here. To get pixel sharp images you need decent glass and great technique.

Viewing 18mp at 100% realy shows faults.

Got to say though I love my 7D, heres some recent heavy crops, lens was 17-55f2.8

From an image like this


To this (not 100% crop yet either):


This is also about a 1/4 frame crop:

[LongQ]

pernod said:

My 2c worth, just to suggest a totally different approach to this problem...

In my winnie-the-pooh brain I'd say the biggest advantage of the 7D if you are looking for extra reach is actually a mix of resolution and it's exceptional ISO performance from a crop body.

Assuming it is reasonable shooting conditions, the ISO performance is more than enough to offset the reduced light from using a teleconverter. While these are known not to give L-sharp images, the extra MP of the 7D means you can down-sample the image to increase its apparent sharpness and still have a large enough image to play with.

I've never actually used a teleconverter on my 7D to test this, but I have down-sampled a few images to increase sharpness with reasonable results.

Thanks for this idea.

I did have an extender in mind but wondered what I could get without it.

I have a 70-300 DO IS lens which gets a good rating so I suspect that it could be close enough to the resolution of a 70-200 +1.4 extender to make that combination a bit redundant. Of course I may be wrong for several reasons in addition to outright image quality.

What I have noticed just recently is that the DO lens images responds quite differently to sharpening, depending on circumstances, than 'other' lenses do. I have read similar comments about 7D sensor derived images as well, especially for smaller size presentation images. It makes me wonder how one can discover, body by body, lens by lens and editor by editor, which PP adjustments are appropriate for each image.

[RobDickinson]

Sharpening depends on so much though, print/view size, detail type etc.

Its not just down to the lens and/or body.

DO lenses seem to be plenty sharp but lacking some contrast?

7d is orsome tho give it a go.

[LongQ]

RobDickinson said:

Sharpening depends on so much though, print/view size, detail type etc.

Its not just down to the lens and/or body.

DO lenses seem to be plenty sharp but lacking some contrast?

7d is orsome tho give it a go.

Hmm. It seems to depend Rob, though I'm not sure I could tell you on what it depends!

Shooting against the light is, perhaps, a bit less satisfactory than 'normal' lenses can be made to achieve - at least it is unless you find a way to PP out the challenges. But in other situations it seems possible to readily lift the images to perfectly acceptable levels of contrast, even files from a 400D. I don't think it takes any more PP then most lenses, though as I always shoot RAW with the dSLR I have an expectation of PP work anyway.

As you say the PP required depends on som many factors that there is unlikely to be a 'one size perfectly fits all' solution but I seem to be able to make things work even across variable monitors with not too much effort per image. (However with a thousand images that becomes quite a lot of effort!).

All of that said - the minimum apertures of the DO lens - f4.5 to f5.6 - are not helpful for DoF limitation with a crop sensor and the 400D and its like will always have the potential ot struggle at the f5.6 end when focusing. Continuous shooting can be a particular challenge. So the f2.8 of the 70-200 could be useful. I can resort to my 600mm ..... but it's old and manual everything and might be a real challenge fitted to a 7D. However an EOS replacement for it would cost more than I can afford, er, 'this week'.

I'm thinking I need to buy a 7D for familiarity to get the best out of it but yet should rent one to get a feel for it in the first instance. Likewise the 70-200. Decisions, decisions. Maybe I will make some calls tomorrow. (er, make that today ...).

[LongQ]

Well - have arranged for a rental of a 7D for this weekend and next when I will, hopefully, be able to add a 70-200 Mk2 to the fun. For the first 'learning' weekend I think my 70-300 DO lens should give a good enough quality to see if any odd issues arise.

One thing I had not reckoned on was the slight scarcity of sources of sensibly priced 7D batteries (more of a problem when I decide to buy one) and the potential cost of some CF cards for the trial since my existing 4GB cards will probably be used up within the first hour! These large, highspeed cards don't come cheap! I was going to rent a couple of those too but apparently that's no longer an option offered.

This could be an interesting few days. I've just read the camera user guide. It didn't seem to complicated, really. What have I missed?

[RobDickinson]

Read up on the 7D's systems first too.

B&H have some good videos and canon has some nice qhite papers and some info.

The AF system is quite complex and setting it up right can be a challenge! if done proerly though you can have 4 or 5 single AF points under your fingers and easy switch to AI servo etc.

4gb card will get about 300 raws on.

You can shoot about 15-18 shots befoer the buffer is full, including writing to a decent card that gets you 22-24 shots.

Be prepaird for a close examination of your gear and technique if you view at 100%!!

[S47]

Don't expect good results over the first weekend, I've had a 7d for 2 weeks and am still struggling with the controls, after 4 years using xxD canons the 7d is real hard work and the learning curve is very steep, I hate the fact that you can't set the buttons up in a way similar to xxD cams, the 7d has one plus point over xxD canons the on off switch is at last easy to use.
The battery last 4 ages so you won't need a spare, though like you say they are stupidly expensive

[LongQ]

RobDickinson said:

Read up on the 7D's systems first too.

B&H have some good videos and canon has some nice qhite papers and some info.

The AF system is quite complex and setting it up right can be a challenge! if done proerly though you can have 4 or 5 single AF points under your fingers and easy switch to AI servo etc.

4gb card will get about 300 raws on.

You can shoot about 15-18 shots befoer the buffer is full, including writing to a decent card that gets you 22-24 shots.

Be prepaird for a close examination of your gear and technique if you view at 100%!!

Cheers Rob.

I spotted the potential 'flexibility' of the AF system. The concept seems undestandable enough but I can imagine that setting it up so that it works thet way you want it to be able to work for the type of shooting in progress could be a brain-stretcher without familiarity with the kit. First proper outing is likely to be Oulton Park for some racing so that should allow to me to restrict the needs somewhat. I hope. Keep it simple and build from there.

I'm surprised at the numbers you suggest. The manual indicates a much larger RAW file, even in mRAW, than my 400D. With the 400D and a 4Gb card I get just under 400 images with a typical file size averaging about 8Mb, +/- 1Mb depending on content. Unless I misread it the manual (Table on 'Page 59' of the PDF) suggest a 25Mb full size RAW file, 15Mb for mRaw and something still quite large for sRaw (11Mb). Thats sounds a bit large to me and your numbers suggest the same. Current cards are SanDisk Extreme III but I'm planning on picking up one or more class 6 UDMA cards by the expected busy second weekend.

I take your point about 100% veiwing. It will be interesting to see what changes I need to consider to my PP work flow (such as it is) to get the best out of it. Even with the current kit I keep finding new opportunities that provide noticable improvements for very small adjustments. In fact it seems to be the micro-adjustments that make all the difference. The downside is that every half decent image may need special attention before one can assess its potenetial. With the volume shooting capability of digital kit that becomes quite an overhead!

Thanks Rob and everyone for the input. Should be a fun few days.

[minky monkey]

I use a 16gb in mine and get around 500 odd large Raws. It is worth having a proper read of the manual if you can, it's the only camera I've ever felt the need to do so!

Edited by minky monkey on Wednesday 25th August 11:48

[LongQ]

minky monkey said:

I use a 16gb in mine and get around 500 odd large Raws.

That suggests the Canon manual numbers are about right then. Hmm. What size card to order?

I can easily run to 1000 frames a day even with only the occasional 3.7 frames per second burst from the 400D. Should I mortgage the house and buy a 32Gb card or two?