500 x $10K or 600 x$13K

[victorwol]

Thanks for all the advise....   a lot of good reading.

[victorwol]

I've never done the 'how slow can I go' test, but I normally use a min shutter of 1/250 s.  As for technique, the usual - good stance, elbows against body with the left one braced to support the lens, eyecup against forehead as an additional contact point. The corners aren't as sharp as the center, but that's a relative thing - they're still sharper than most other lenses...

Definitely the right technique but I've noticed some people are simply better at handholding than others. I'm guessing you haven't compared yourself to others who atleast know how to support the lens. The 1/250th is with the 2x extender on right? Other question is have you compared the resolution of a 7D and 1.4x vs a 1dx and 2x? I know you'll take a big hit in AF and probably a little more than a stop of light (I'm guessing about 2.5 stops difference in low light performance, I'm assuming the 7D at 800 is similar to the 1dx at 4000ish in RAW noise level). Important thing to think about too is the 7D has the same MP and a higher effective magnification (1x2x600=1200 vs 1.6x1.4x600=1344). I'm really interested to see how a crop sensor can measure up to a FF on focal length limited applications. I realizing I'm asking a lot but I figure it might be an interesting comparison if you feel up to it. Thanks for the info, the wheels in my pixel peeping mind are turning  .

In response to the OP because I'm getting off topic: If shooting is a hobby the 500mm does sound like a better option. The added weight certainly will not add to your enjoyment of photography. The extra 20% magnification is not a big deal especially when it's really only about 10-15% magnification if you are cropping because the 500 is certainly a sharper lens. Plus the cost difference is extra money for vacation and that seems like a better use of the money. Also if your subject is between 12-15 feet not having to use tubes sure is nice.

Are you saying the 500 is sharper than the 600? May I ask where you got that information?

Thanks!!

[Stu_bert]

I'm really interested to see how a crop sensor can measure up to a FF on focal length limited applications.

Me too, and I've been planning to do such a test for a while, but haven't gotten to it yet.  Besides curiosity, I want to determine if there's a point in my keeping the 7D (other than purely as a backup camera).

Obviously not everybody has seen my comparisons yet, though I know Neuro has

These were shot to determine if I would gain any advantage with a 7D, I set it up in ideal conditions that very much favoured the crop camera. After seeing these I determined a 7D was a waste of my money although there are very good reasons for others to get one, however thinking you are getting extra resolution in focal length limited situations in real world shooting, ie, AF, IS, panning etc etc is not one of them.

Left hand image is full 1Ds MkIII image with 7D image from the same place with the same lens marked in red, right hand images are very tight over 100% crops, this equates to very sizable prints and from a couple of feet or so away I can't tell the difference in resolution. If you look closely the 7D does have more resolution (and noise), but I found in real world shooting situations that extra just wasn't realisable. Don't forget, in these two crops the 7D image has over twice as many pixels as the 1Ds MkIII image.

I may be missing the point, but I though the comparison requested was between a cropped sensor vs FF with an extender? Did your comparison include the extender on the 1Ds? Apols if it did.

[neuroanatomist]

After seeing the results I got without one I knew there was no point in me testing with one, I even had a 1.4 and a 2x TC to hand at the time, though I no longer have the 7D so can't repeat the tests, but, for me, the results without a TC were conclusive enough to realise a 7D wouldn't serve me a useful purpose.

Still not exactly the point - the question was actually a comparison between the APS-C (1.6x) with the 1.4x TC (so, 2.24x total) vs. the FF with the 2x TC, in other words, is the better IQ of the FF sensor sufficient to overcome the greater decrement in the optics with the 2x vs. the 1.4x TC.  It's relevant because in the case of an f/4 lens, the 1.4x TC allows normal AF on the 7D (all points) whereas the 2x TC on the 1D X allows only a central cross-type point and 4 surrounding single-line points. 

[natureshots]

After seeing the results I got without one I knew there was no point in me testing with one, I even had a 1.4 and a 2x TC to hand at the time, though I no longer have the 7D so can't repeat the tests, but, for me, the results without a TC were conclusive enough to realise a 7D wouldn't serve me a useful purpose.

Still not exactly the point - the question was actually a comparison between the APS-C (1.6x) with the 1.4x TC (so, 2.24x total) vs. the FF with the 2x TC, in other words, is the better IQ of the FF sensor sufficient to overcome the greater decrement in the optics with the 2x vs. the 1.4x TC.  It's relevant because in the case of an f/4 lens, the 1.4x TC allows normal AF on the 7D (all points) whereas the 2x TC on the 1D X allows only a central cross-type point and 4 surrounding single-line points.

I do use back button focusing and recompose while leaving the AF in servo. Kinda gives you the best of both worlds so I'm primarily using just the central sensor unless I have extended time to switch AF points which is frequently not the case with erratic wildlife. If I was to guess I would say that the 7D with 1.4x will outperform the 1dx with a 2x unless the light gets low or you need great AF. Other variable in the test is the decreased precision of the 7D's AF points. Accuracy can be fixed with AFMA but I've seen a comparison of the precision between the two cameras and most canon FFs perform better.

[natureshots]

After seeing the results I got without one I knew there was no point in me testing with one, I even had a 1.4 and a 2x TC to hand at the time, though I no longer have the 7D so can't repeat the tests, but, for me, the results without a TC were conclusive enough to realise a 7D wouldn't serve me a useful purpose.

Still not exactly the point - the question was actually a comparison between the APS-C (1.6x) with the 1.4x TC (so, 2.24x total) vs. the FF with the 2x TC, in other words, is the better IQ of the FF sensor sufficient to overcome the greater decrement in the optics with the 2x vs. the 1.4x TC.  It's relevant because in the case of an f/4 lens, the 1.4x TC allows normal AF on the 7D (all points) whereas the 2x TC on the 1D X allows only a central cross-type point and 4 surrounding single-line points.

True, not exactly the point, but as so often we can become in danger of over thinking this. If you agree there is no practical difference in output between my two crops, and at reasonable viewing distances in print and on screen I have satisfied myself that there isn't, especially when used in real world shooting scenarios, then the obvious extension of that is to get similar results from the 7D and 1Dx you don't need to use different TC's, just slap the 1.4 on the 1Dx and crop, your results will be exceptionally close to mine.

The second thing I found that killed the 7D for me was noise, even in well illuminated situations at base iso you can see more noise than with a cropped full frame, start shooting in less ideal situations and the differences just get bigger.

As always, I am not saying the 7D is a bad camera, it is not, and I am not saying you can't take superb images with a 7D and print them big, you can. It is just that, IMHO, if you own a decent megapixel full frame body with good AF then there is no realisable IQ reason for you to own a 7D as well.

So, when you do get round to doing your testing, make sure you compare both with a 1.4TC and crop the 1Dx, you might be surprised.

For those of us that do small birds we tend to use really long lenses/extender combos and crop (focal length limited photography). I'm guessing that the 7D + 1.4 will pretty thoroughly outperform the 1dx + 2X in good light. If this is what your primarily doing the 7D can make a big difference. Also, when they update the 7D which will hopefully be coming soon I would hope that the low light performance will increase by a stop. If so, the 7D mkII will be a huge boon for bird photography so I'm kinda curious how everything comes out. It's important to remember that the 7D combo puts a good deal more pixels on your subject and offers tighter framing while avoiding the less sharp corners of the 1dx + 600 + 2x TC. Also you have the ability to put on a 2x on the 7d and I can 100% guarantee that you will get better results than the 1dx and stacked TCs. Its a nice option to have for some bird photographers who can MF and simply cannot get closer (yes, plenty of bird photographers have made sale-able images with stacked TCs). For those people who want to do pro photography this edge for focal length limited stuff is huge and can make a difference in your income. If you want to make the comparisons check out the digital picture. Too bad they don't have the 100% crops from a crop camera and the 600 combos .

[AlanF]

Agree with Natureshots. Beyond a certain distance, you cannot theoretically and in practice resolve two lines at a particular separation That critical distance for any camera and sensor depends linearly on the focal length of the lens and linearly with pixel density. If the critical distance is 20 yards for a 500 mm lens, then it will be 24 yards for a 600 mm. If your subject is between 20 and 24 yards away, the 600 will work and the 500 won't resolve (all things being equal). But, if the subject is less than 20 yards away, both lenses will resolve the subject. Similarly, if the 20 yards is for a typical FF, then the 7D will get you out to about 30 yards. So, between 20 and 30 yards, the 7D will work and the FF won't resolve. Below 20 yards, the FF will beat out the 7D. So your test shots depend on what you are photographing and how far away it is.

[danski0224]

The obvious choice is 600 x $13k because it is more than 500 x $10k.

That's what I would want.

 

[neuroanatomist]

So, when you do get round to doing your testing, make sure you compare both with a 1.4TC and crop the 1Dx, you might be surprised.

Probably not.  The reason I haven't been terribly motivated to set up the test is that I've done the test between the 7D and cropped 5DII (about 18 months ago, now), so I know the only difference is MP not IQ, and the 1D X is better than the 5DII for sensor IQ.  I assume the test with the 600 + 1.4x on both bodies would show the same, or an advantage to the 1D X at higher ISO. That test is less relevant now that the 1D X supports f/8 AF - not much difference in pixel-level magnification comparing 2x on FF to 1.4x on 1.6x crop.  I disagree with natureshots that the 7D + 1.4x will optically outperform the 1D X + 2x.  That might be true with a lesser lens, but the MkII supertele lenses just don't take that big an IQ hit from a TC, even a 2x (and keep in mind that the 600 II + 1.4xIII beats the 800/5.6 for IQ).  As for AF, while the 7D's 19-points are very good, the center point of the 1D X is better.  But the real kicker is that most times I've been out shooting with the 600 II, my ISO has ranged from 1600 to 6400. The bottom of that range is ok on the 7D, but the top end just doesn't cut it on the 7D. 

For those reasons, I'm pretty sure the 7D gives me no advantage over the 1D X, other than a few more MP (and not really all that many more, comparing the 1.4x on the 7D to the 2X on the 1D X.

The question I suppose I'm really asking myself is, do I want to keep the 7D as a backup body?  Or should I take what I can get for it, now, and put that money toward a 24-70 II?

So, between 20 and 30 yards, the 7D will work and the FF won't resolve. ... So your test shots depend on what you are photographing and how far away it is.

Would you expect that to be true at, say, ISO 6400?

[Stu_bert]

So, when you do get round to doing your testing, make sure you compare both with a 1.4TC and crop the 1Dx, you might be surprised.

Probably not.  The reason I haven't been terribly motivated to set up the test is that I've done the test between the 7D and cropped 5DII (about 18 months ago, now), so I know the only difference is MP not IQ, and the 1D X is better than the 5DII for sensor IQ.  I assume the test with the 600 + 1.4x on both bodies would show the same, or an advantage to the 1D X at higher ISO. That test is less relevant now that the 1D X supports f/8 AF - not much difference in pixel-level magnification comparing 2x on FF to 1.4x on 1.6x crop.  I disagree with natureshots that the 7D + 1.4x will optically outperform the 1D X + 2x.  That might be true with a lesser lens, but the MkII supertele lenses just don't take that big an IQ hit from a TC, even a 2x (and keep in mind that the 600 II + 1.4xIII beats the 800/5.6 for IQ).  As for AF, while the 7D's 19-points are very good, the center point of the 1D X is better.  But the real kicker is that most times I've been out shooting with the 600 II, my ISO has ranged from 1600 to 6400. The bottom of that range is ok on the 7D, but the top end just doesn't cut it on the 7D. 

For those reasons, I'm pretty sure the 7D gives me no advantage over the 1D X, other than a few more MP (and not really all that many more, comparing the 1.4x on the 7D to the 2X on the 1D X.

The question I suppose I'm really asking myself is, do I want to keep the 7D as a backup body?  Or should I take what I can get for it, now, and put that money toward a 24-70 II?

Backup body is frankly always worth it IMO, especially if you take any sort of "costly" trip where swapping / repairing a body is impossible...

But although I agree with what you have said, I also thought part of the point of the tests were to give the OP options on 500mm vs 600mm. Appreciate you don't have the 500mm but would it not be valid to compare 600mm with 1.4x to 600mm with 7D ie is the crop sensor better than a 1.4x converter or indeed 1Dx with 2x vs 7D? If the 7D with 1.4x was equal to 1Dx with 2x, then might that infer a 500mm with crop sensor could be a viable alternative to 600m / 1Dx. Appreciate the comments on AF and ISO and the OP has a 1Dx

On your original test - the 7D had the same IQ as the MK II, but "higher MP" based on FOV? Was that with extenders as well by chance?

[neuroanatomist]

I did a 'quick-and-dirty' test (static scene, not my ISO 12233-type chart) soon after getting the 600 II, comparing the 7D vs. 1D X + 1.4x.  The 1D X + TC was a little better at ISO 100 and a lot better at ISO 3200.

The original test was with the 100L, no extender. The point was to simply compare the crop sensor vs. cropping the FF image to match FoV.

[Lnguyen1203]

How did this thread go from 500 vs. 600 to cropped sensor vs. FF?  He already have a 1DX and is not asking about 7D vs. 1DX plus 1.4X.

[neuroanatomist]

How did this thread go from 500 vs. 600 to cropped sensor vs. FF?  He already have a 1DX and is not asking about 7D vs. 1DX plus 1.4X.

Because fundamentally, that's a question only the OP can answer for himself.  What else is there to say?   

[Stu_bert]

I did a 'quick-and-dirty' test (static scene, not my ISO 12233-type chart) soon after getting the 600 II, comparing the 7D vs. 1D X + 1.4x.  The 1D X + TC was a little better at ISO 100 and a lot better at ISO 3200.

The original test was with the 100L, no extender. The point was to simply compare the crop sensor vs. cropping the FF image to match FoV.

Cool thank you.

[Stu_bert]

How did this thread go from 500 vs. 600 to cropped sensor vs. FF?  He already have a 1DX and is not asking about 7D vs. 1DX plus 1.4X.

Err does it matter  ?