IQ of 7d w 15-85mm Vs 6d w 24-105mm?

Started Mar 8, 2013 | Questions thread
MAC
MAC
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Re: 24-105mm rated 50% better than 15-85 at dxo
In reply to qianp2k, Mar 11, 2013

qianp2k wrote:

MAC wrote:

He's not weighing all information. And he is quoting dxo who is not transparent with how they did the MPix testing. You've experienced similar results up to 20x30 between crop and 5dii at base iso for scape type of shooting -- and that would be my conclusion as well -after weighing all of the information

DXOMark P-MPix concept

I print a few of my photos to 30x20". 5D2 and 5D1 prints are noticeable sharper than from 60D at the same size. I own all these cameras - 5D-5D3, 60D and 1D3.

a few...hmm

one needs to process photos - processing evens the tables

yep, you believe dxo, that 1d3 is giving you 10 Mpix or less...

and that 5d2 is only giving you 12 Mpix with that 24-105 zoom -- note, I get 12 Mpix with my 5dc and primes.

When one buys a 5d2, don't they expect 21 MPix?

dxo is really going to confuse buyers of the 5d2/6d/5d3 on that one

5dii/6d comes into play with the primes and higher iso's for shallow dof. But I'm liking my 60d/T4i all the way up to iso 3200 and with processing, getting sharp, nice photos with my primes and a lot less weight -- and at 1/4 to 1/2 the costs

Put your personal preference aside, 6D and 5D series are noticeable sharper than Canon 18mp APS-C cross entire ISO range. APS-C does has operation advantages such as smaller/lighter bodies with EF-S lenses that have limited choices. Same true for mFT and other mirrorless if you want further smaller/lighter gear.

well, I've found when I process my 60d images properly, the sharpness is really nice.  And if you read TDP, you'll find out that my T4i RAW images are tuned to 1dx sharpness level right out of the camera -- in RAW.

Even if you believe dxo within 1 to 2 MPix units error, and I'm not saying I do because if they changed the distance, all bets are off -- and comparing resolution across formats is not apples and apples, but even if there is some truth to it:

For a meaningful comparison, you need to frame the subject into the same AOV for the same scene otherwise you ended with two difference cameras. That's why you use EF-S 15-85 on 60D while I use 24-105L on 5D. 15mm on 1.6x crop is equivalent to 24mm on FF. The reason you can use 15mm to achieve 24mm AOV is thru 1.6x crop magnification. You win convenience and operation advantage but you suffer 1.6x more enlargement that inevitable cause mushy pixels and IQ loss in other areas.

difficult to do -- unless you use a zoom.  You need to keep the distance the same for any kind of meaningful cross format comparisons

How did DXO test MPix?  We don't know  1) how they tested? 2) what 1 number means?

I think they made a mistake with the crop, and sent it to farther distant places -- an error in testing

you talk about crop suffering...oh, give us a break

1) 12 Mpix is sad number from 5dII plus 24-105. Within an error of 1 or 2, and for 1/4 to 1/2 the price with primes, my 60d or T4i gets 10 or even 11 -within experimental error -- no difference. Use my 35 f2, or 50 f1.4 or 100L or even use my 5dc. 12 MPix is not a good number for a 21 MPix 5dII with a zoom lens

12 MPix from 24-105L on 5D2 is still much higher than 8 MPix from 15-85 on 7D/60D (EF-S 17-55/2.8 IS should have similar number). You can get a copy of 24-105L new today around $800 that is cheaper than EF-S 17-55/2.8 IS and only about $150 more than EF-S 15-85. But 24-105L is a constant F4 L zoom and weather sealed. None of EF-S lenses are weather sealed. 15-85 is too slow at F5.6 in tele side.

Not if they tested the crop wrong by moving it further from the subject -- there results then would be invalid to compare across formats.

5dii though testing at 12 MPix with the 24-105 might be valid -- but I can use my 5dc to get 12 MPix.

2) And I expect the new sigma 30 art to be even higher.

Now you switch the topic to prime. So far Canon only has one EF-S prime (60/2.8 macro) so some third parties fill the gap such as forthcoming new Sigma EF-S 30. However Sigma 50/1.4 on 6D still beats Sigma 30 (EF-S) on 60D comfortably. I'd not suggest OP to build up EF-S lenses as sooner or later OP will move to FF (if not this time) then all those EF-S lenses will not work on FF.

I enjoy both EF-s lenses and EF lenses-- 1 FF + 2 crop cameras

3) We're talking a 4x zoom with the 24-105 versus a 5x+ zoom with the 15-85 -- last I checked, more range with 5x zoom

More super-zoom more sacrifice in IQ. 24-105L is a constant F4 zoom with weather sealed. EF-S 15-85 is a variable F3.5-5.6 zoom and not weather sealed. 24-105L has much better build quality.

15-85 has 20% more range and a stop better IS.  And dxo didn't test crop cameras for MPix correctly to be compared across format platforms

4) 15-85 has better IS as well.

24-105L has at least 3-stop 'IS' and I am able to take shoot at 1/6 sec hand-held. And don't forget 1.6x crop suffers 1.6x more vibration so before 'IS' (that is not guaranteed), you'd need 1/<focus_length>*1.6 min shutter speed.

24-105L on 5D2 in Alaska trip - in rain, hand-held at 1/6 sec.

post comparison images versu N=1

You've posted that same girl all over dpreveiw.  Do you know her 



5) After processing images at base iso, things level even further. Those looking at 100% pixel peep will be misled. One should look at prints after processing -- and even large prints iso100-400, one will not see differences

At 2000-pixel wide, I already can see 5D2 is noticeable sharper than photos from my 60D even at base ISO 100. And don't forget FF is not just better in natural sharpness, it also better in many other areas - SNR, clarity, color tonality and smoothness... I can see noticeable grains in dark blue sky and shadow areas from 60D photos. 5D series photos look noticeable cleaner in shadows also at base ISOs.

You should try my T4i that is tuned to 1dx RAW sharpness standards -- right out of the camera

6) he has refused to take blind test on prints

Nobody can see your prints. I can see my prints but not yours. We all can see JPEG photos on internet however

post your full size comparisons -- side by side -- or it didn't happen

7) dxo will get one into a bunch of wondering and mis-information when it comes to real shooting.

Sure DXOMark also makes mistakes likely other sites. But DXOmark is still one of the most reputable and well respected site.

How did they test MPix?

Can you compare MPix across format platforms when you change distance -- NO

8) He has the 60d + sigma 17-50, and should know that on the prints made by him (he does little printing and a lot of pixel peeping), there will be no difference. So why spend the 2x to 4x extra money on more weight -- with no sales. His wife will carry the extra weight on vacation. Go figure.

Yes Sigma 17-50/2.8 OS. At 30x20" print, 5D2 photos are noticeable better and sharper. Yes I print but occasionally. Please don't exaggerate of cost and weight difference. You only have very limited EF-S lenses choice. How about 70-200L/4.0 IS, 100-400L, 70-300L and many primes that are all EF lenses. With some good lenses the difference between bodies become much smaller.

my T4i is my light weight, one hander.  I sure do enjoy with my 35 f2 and 50 f1.4 and toki 10-17.

The problem gianp2k is -- that you trash talk crop setups.  You do it with data that you don't understand the method or the numbers behind the method.  DXO shows my T4i is behind in overall score from my former 40d.  That is not only nonsense -- but a joke.  To have credibility -- one needs to provide credible ratings.

Do you know for sure MPix is credible to compare across formats?  I think you don't know how they did the testing.  If they changed distance, they violated the fundamental rule of equivalency -- the distance between the sensor and the camera must remain the same.

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