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Rx100 sharper than 24-70 FE @ 70mm


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I did some tests today as I have been getting some poor focus at 70mm on my 24-70FE

I mainly do landscapes but play around with some portraits and wildlife when I get the chance, but recently a bird shot came out tack sharp on my partners RX100 and my carefully manually focussed shots on my A7r 24-70FE at 70mm were not tack sharp at all.

 

I since realised I should have increased ISO to get the shutter speed up to at least 1/250, some of my poor shots were at ISO 100 1/45

 

To further explore I mounted both cameras on a trpod at home today to photo this lamp and can conclude the RX100 is deffinitily sharper at 70mm,

(approx 70mm equavellent as the RX100 is supposed to be a 28-100 equivelent focus lens, exif reads 37mm but it was near full focus length)

 

I just cant get a tack sharp image from the 24/70 at 70mm?

  • I used remore trigger
  • mounted on a stirdy tripod
  • Increased ISO to get faster SS
  • Used remote release
  • Manually focussed maticulously
(the image did become tack shap in the viewfinder but not the raw output file viewed in lightroom)
  • I tried with both image stabilisation on and off, both images were identical
(I recon its a myth by the way that image SS on or off on a tripod monted A7r is any different, please reply if you have found there is a difference)
  • Tried mounting weight on the lens in case shutter shake was effecting at 1/200 but interestingly this blurred the picture

     

    This is really disappointing, I don't want to fork out for an 85mm prime for portraits and I can't carry that around on my landscape hikes in case I encounter wildlife, I really hoped the 24-70 would do a better basic job than this, especially compared to a camera with a tiny sensor, the rx100 is a great little camera but it's disappointing that a $400 camera beats about $3,500 worth of kit for the A7r & 24-70FE.

See below images, all from RAW files with minimal development, 3:1 zoom in Lightroom, the first one is the best of about 8 I took.

 

A7r 24-70FE 70mm F4 1/250 ISO 1000 not sharp at all?

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RX100 Approx 70mm Equivelent, 1/100 F4.5 ISO800, tack sharp

 

So I tried the 24-70 FE @ 55mm F8 ISO 3200 and it improved a lot, its close to the Rx100 now, but thats the Rx100 at f4.5 70mm so that may not be an equal comparison, I still think there is more detail on the Rx100 but its close, ISO noise is stronger on the RX100 so I am unsure which is best.

 

There is a strong red hue from the A7r? I guess thats the Auto White Balance many give out about, interesting any feedback on the red hue as I have that on all my photos, does not seem right, is this the auto white balance? I could swear its there when I select white balance in camera myself.

 

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Really, bad copy eh, are you saying that you can get tack sharp at 70mm at 3/1 zoom in Lightroom?

 

 

As you can see my sharpness is shockingly terrible at 70mm, I might send it back to Sony for testing then. I will do some test shots with it vs my 16-35FE at 24, if it's faulty it should show up then, will update later.

 

 

 

 

I got the RX100 v1 for my partner 9 months ago, I could not justify the extra cash for other models but did end out getting a wifi SD card for $100 so prob should have bought the mk2. It's a great little camera, fast focus, fast everything except flash but that's expected, it's a gem.

 

 

Steve,

Lawlors Landscapes

www.lawlor.me

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Try putting the camera on a tripod, turn Imagestabilisation off, set the timer to 10 seconds and the shutter speed to something very slow. About a second or so.

Just to be sure you're not experiencing shutter shock.

 

Also is this zoomed into the middle or the corner of the image? The corners tend to be bad on the 24-70...

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I just went through and looked at some images from my 24-70mm f4 at 70mm f4, and they look nothing like your image.  My lens is sharp at that focal length and aperture.  I am not at home at the moment, but I will post some comparison images later today when I get home from work.

 

-J

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As to shutter shock, you can use the lamp's

own power switch to control exposure time.

 

Even if you don't have a poor example of the

28-70, do consider that you are comparing 2

zoom lenses where the "loser" is all the way

out to its long end and the "winner" is near

its midrange.

 

OTOH, if you were to shoot the RX100 at its

long end, and increase subject distance so

the subject is framed equivalent to the long

end of the 28-70FE ... THEN if the RX100 is

still distinctly sharper you'd have quite the

phenomenon. Not that I'm predicting results

either way, just thinking that a long end vs

long end comparison might be informative.

 

One other thought. Because your subject is

self illuminated, you're not only testing lenses

but also sensors. To narrow down to just the

lenses, try using a more normal subject.

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I did some more testing but indoors at night,

Not bothering to post the sample images as ISO came into the mix which stops me from tellling if there is shutter shock, I need to test again in daylight.

 

Yali,

Longer shutter times did clear up the image, anythig from 1/60 to 1/250 was blurred but they were at ISO 1600 and 6400,

I suspect the longer shutter speeds (1/6 & 1') at ISO 100 were better as they removed the grain of higher OSO, maybe shutter shock also? I will test again in daylight to rule ISO out of this mix will do by the weelend and report back.

 

Jlw518,

Please do post some samples

 

Golem,

You are quite right, the Rx100 (Mk1) at full zoom (100mm equivellent) degraded near the level of my 24-70FE @ 70mm, it still looks a little better however its close so thanks for pointng this out. Another thing I did notice is the RX100 autofocus was spot on with my manual focusing but the A7r autofocus was just terrible, I tested on all 3 size flexible spot, I will test that again, maybe a new post for that examination.

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There is an image limitation in each post of 1mb so I had to start a new post for the conslusion of this,

 

http://www.sonyalphaforum.com/topic/3734-rx100mk1-sharper-at-full-zoom-than-2470fe-v2/

 

If you want to add your 24/70 images start a new post and paste a link to it on the second blog i started above.

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