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Sony SLT vs. NEX for photography with astro-telescopes (1 Viewer)

DRodrigues

Well-known member
From Thread http://www.birdforum.net/showthread.php?t=194789&page=43 I collected information that might be useful for someone thinking on this issue, so I hope to avoid the loss of this information. Thanks Fernando for sharing your opinions and practice!:t:

At post #1073 Fernando Batista mentioned “At this point I would say it’s the best digiscoping camera in the market (either this or the A77 depending on your needs), At least for me.
That said, I still have some mixed feelings about it, it’s really good in some respects, but could be quite better on others.
The upsides:
I bought it for one reason mainly, focus peaking. It’s a remarkable function, it’s the easiest way to focus on steady subjects I’ve ever used, period. Seeing what is in focus couldn’t be easier than this.
Than there’s that amazing EVF, it’s huge, it shows exactly what your picture is going to look like, it’s very sharp and clear, even in lower lights. Much better than the G5 EVF I had previously.
Still, I added a 1.35x magnifier to it, now it’s like focusing on my living room TV.
Being used to the 450 OVF you’re going to love the view from this, also you’ll see the true DOF you’re getting, I found that very helpful in focusing too.
The steady shot, you have to chip your scope to take advantage from it, but it works quite well, especially in video mode.
Speed, this camera is fast, really fast. 3.5fps with live view, that’s about average for an EVF camera. But you have the option of 10fps too, and it writes those shots to the card very fast for a camera at this level.
Of course at 10 fps it no longer gives us live view, but it’s slide show effect is very fast, again much faster than the G5 I had. Overall it just feels very snappy.
Resolution, I’ve never seen so many feathers on a bird shot until I bought this, the detail is incredible. On the other hand, missfocus and shakiness now becomes quite obvious.
Silence while working, this is a feature I start valuing a lot lately, and this camera doesn’t disappoint, is not completely silent like the G5 but is very discrete, and using the front curtain option even more so. I don’t think I ever had a bird flying away from the shutter with the A65, this was a real problem in some locations with the D90.
Now for the downsides:
ISOs are a bit strange on this camera, when I first view the files from the camera I found them very noisy indeed. But comparing side by side to my D90, showed me that the ISOs from the A65 are very different than the ISOs from the D90. Basically, shooting the same scene with both I had to increase the ISO on the D90 by almost 2/3 of a stop to get the same shutter speed of the A65 and the same histogram.
Now I find myself shooting a lot at ISO 100 and 200 a lot, while on the D90 I rarely dropped from 400.
I don’t know if it’s just my camera, but mine is definitely more sensitive for the same ISOs than the D90 was.
Trap focus, you don’t use it, but is something I loved on my D90. And the trap focus on the A65 just doesn’t work reliably. Still I can’t complain about it because most other newer cameras I tried don’t work as well as the D90, that goes for the D7000 and D300 too.
Focus peaking, is really good… but could be even better. And this is the point that’s going to make me change this camera sooner than I though.
Sony’s peaking uses a type of CDAF detection, it reads only vertical structures. With that it’s sensitivity is less than optimal. And in some cases it doesn’t even show enough peaking.
To work around it, I have to increase the effect to mid or high, the problem with this is the shown peaking is more than the image DOF, so precision is lost.
Also, detecting only vertical structures causes peaking effect to disappear when panning horizontally, witch is an obvious problem for BIFs.
I hope sony improves this at some point, for example a focus peaking like Fuji is using now seems to be best. From the videos I’ve seen on Fuji it’s peaking seems to detect vertical and horizontal features and detects far more detail than sony’s.”

At post #1100 I questioned Fernando “…I'm curious why you consider the A65 better then the NEX7, besides price, for using with astro-telescopes for photo. The NEX7 image quality should be even better since no light is lost by the translucent fixed-mirror of the SLTs. I'm waiting for a future NEX5 version with the 24M sensor or that the future NEX6/7 versions with this sensor will decrease price but might consider a SLT if there are advantages when using it for photo with astrotelescopes... ”

Fernando replied at post #1103 “…Well, I did say “for me” So keep in mind this is just my personal opinion, each user will have it's own preferences and priorities.
The mirror is a non issue if you're using MF lenses only, just remove it and you'll have the exact same sensor quality of the nex 7. It's very easy to put on or off.
For me, the advantages over the nex are:
- A real body with a real good grip and important direct buttons. The NEX body is a bit on the small side, I could easily use it off course, but with the telescope I really prefer a DSLR style body.
- Better battery life.
- Trap focus, not so good as Nikon D90, but better than D7000 (I do keep the mirror for that though). On the NEX7 this can't be done.
- IBIS, on a good tripod is not so important, but it is nice to have it when need. And for video it's very useful even on a tripod.
- Price, is a good deal less than the price of the NEX, for digiscoping alone I can't see any advantage in paying for the current NEX 7.
The A65 being the best digiscoping body is my opinion based on the currently available bodies, that will probably change in a not so distance future. Both the rumored NEX7n and Panasonic G6 have very appealing features for me, and I may get one of those.”

As I'm not mainly a photographer, I prefer the small body of the NEX, specially with the recent 16-50 zoom, since uses much less space on my field bag...3:)
I also do some "traditional" digiscopy and the smaller size of the NEX is also better. I also think the NEX versions are pricey when compared to SLT and I wish there would be a Bigma 50-500mm NEX version to use for video - the only use where I really miss the auto-focus on my TMB92/NEX5 combo...;)
 

FernandoBatista

Well-known member
Hey David,

In your situation I'm not surprised you prefer the NEX, you don't use your scope only for photography so your camera is just one more accessory in your backpack, of course you would want it as small as possible. Like I said everyone will have is own priorities.

In my case though, my camera is atached to the scope 99% of the times I press the shutter, and the scope is used with the camera on the back 100% of the times, so for me a few more centimeters here and there on the camera really doesn't make a diference. The overall system is still going to be huge.

That said, in the other 1% of the times I use the camera I would mostly prefer a NEX, walking around with the kids, traveling, etc. And I do look a lot at the NEX and M4/3 line thinking of that.
At the time though I wasn't willing to spend 500€ more on the NEX7, and lose PDAF.
With the rumored NEX7n coming, or even the OM-D replacement this may change, will see.

BTW you say you miss AF with the NEX for video, why? Video is one area where most people would prefer MF. I surely do, for video I really don't want AF at all.
Your camera has focus peaking too, you should do just fine with it.
 

DRodrigues

Well-known member
BTW you say you miss AF with the NEX for video, why? Video is one area where most people would prefer MF. I surely do, for video I really don't want AF at all.
Your camera has focus peaking too, you should do just fine with it.
You are probably right since I only managed to update my NEX5 system version last February and the January storm ruined my photo/video season that is usually in February/March - flushed most ducks from S. Jacinto main pond... So after having focus peaking I never did video there and was writing from my previous experience since ducks move much (have a look at the videos at Fotos at www.pt-ducks.com), and with auto-focus I would had to cut less the videos...;)
I was waiting to reply you after testing video with focus peaking but still didn't managed to have an opportunity in good conditions...|=(|
Will try during the next weeks and will report.
 

DRodrigues

Well-known member
new Sony 3000 series

After some experiences I still don't make much benefit from focus peaking, including on video. Don't know if focus peaking version of my first series of NEX5 doesn't work as well as on later versions and SLT versions that already included this function originally?...

Meanwhile I noticed Sony is releasing a new series of mirrorless cameras that will have interest for photography with astrotelescopes http://www.dpreview.com/previews/sony-alpha-a3000 although this version has a not so good EVF/LCD resolutions. Maybe a latter version.

The new NEX5 version http://www.dpreview.com/news/2013/0...ource=news-list&utm_medium=text&ref=title_0_7 still has a 16.1 mega sensor - if had received the sensor of the a3000 I would probably purchase it so will wait more a year...
 

FernandoBatista

Well-known member
Are you using the external EVF? or the camera's back screen?
If it's the screen I'd strongly advise you to get the EVF or a camera with EVF.
I tried using the back screen a few times when I'm sitting on a hide, mostly photos turns out OOF. It's much easier to focus from the EVF, at least for me.

Still you have to take some care with peaking, you have to find it's strongest point by going back and forth, a bit like hunting for detail in an OVF, although it's much easier to find the peaking strongest point than the strongest detail.

That's why I said before peaking has yet to be perfected, as it is it shows more DOF than the actual image, it would be perfect if it showed the accurate DOF or even less.
 

DRodrigues

Well-known member
purchased a a6000

After waiting for a year I finally decided myself and purchased a a6000...o:D
Still learning the camera but is good for digiscopy http://www.birdforum.net/showthread.php?t=280498 and for astrotlescopes use.
I enclose the first results that allows to study the diet of Ixobrychus minutus...:king:

For those not needing EVF and 11 fps there is the new a5100. It would be interesting for me if it had 11fps... Although not using the EVF of the a6000, I do appreciate it's extra buttons...3:)
 

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