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Sony A7R IV announced ...
#21
(07-19-2019, 02:06 PM)JJ_SO Wrote: Blurb aside, my question was why Mark Smith doesn't tell us anything negative about shutter lag?

My next question will be which are your personal experiences with that Sony? Why should we care about shutter lag with exotically long FL? And which DSLR will focus accurately at 1200/8? Who cares about small shutter lag if the picture is out of focus? How often did you shoot with 1200/8? Or more likely with 1200/12.6 because that's what your current Tamron delivers.

Why should we care about 120 Hz refresh rate, if it remains uncertain what the refresh rate has to do with shutter lag?

What, besides another typical YouTube "issue", is the real world significance?

I follow his videos, they're very good !

..... it's not the shutter lag .... but the refresh rate. (1200mm)
 You get a new EVF image every 1/120 sec. ..... so effectively you hang on to the same image until the next update 1/120 th sec. later ...... meanwhile the birds moved on without being able to see it advance in the viewfinder.

Mark probably has no need of those longer focal lengths he's always near to them.
Dave's clichés
#22
Hmmm, I don't think I could handhold a 1200 mm lens - which is by far creating the most troubles for a viewfinder - but even more so to myself. Settling the lens on a stable tripod and a solid gimbal is for this kind of FL essential. And then the refresh rate will be sufficient, except when chasing rather fast subjects moving across FoV.

Next to that: Even if an OVF has no refresh rate (but our eyes also can't process pictures with infinitely fast speeds), the AF-module of a DSLR also has a refresh rate (I don't know how fast that is, hopefully faster than only 120 Hz).

This kind of complaint is rather academical. The time I need for framing is sooo much longer than 1/120 sec, I simply don't care about EVF refresh rate. If I turn the lens in 1 sec 90° horizontally, I would theoretically get a picture each 90/120 degrees (or each 0.75°. But do I need to see smaller angles? Could my brain process these 120 frames per 90° turn? I have a lot of doubts about how signficant this "scientific findings" are.
#23
Shutter lag is unlikely to affect BIF images that much ..... most series of BIF shots are started in anticipation of the bird at the perfect distance and dump the duds... it's single point/shot the will suffer there ....... as in street photography to catch that expression or whatever.

So, the problem is limited to "only" very long focal lengths and panning .......
Dave's clichés
#24
The Z7's Shutter-lag is 0.215 second ....... Nikon D850 ....... 0.076 sec ....... Sony A9 ..... 0.231 secs.

Canon EOS R SL .............. 0.052 secs. ....... Canon 5D IV .......0.077 sec.

Nikon D500 SL .............. 0.049 secs.

So it looks like both the Nikon Z7 and the Sony A9 both have a little longer shutter-lag !

It hardly gets a mention in the forums so I would think that in practice it's a non issue !!


Edit ..... The Sony A7R IVs EVF has 5.6 million points at 60 FPS and is getting lots of praise for it's quality......... apparently at 120 FPS the resolution is less ...... we will have to wait for the wait for the reviews to see by how much!
Dave's clichés
#25
I still think, measuring the shutter lag is a usesless game and I'm very skeptical to believe the values because I have no idea how they measured. I will keep on having no idea because in real life it doesn't help. So I also will not investigate how they measured as I'm sure it will throw up new questions.

What good it is to know a certain amount of shutter lag, if AF has problems to catch focus and I set the camera to focus priority? The Z 7 0.215 = 1/5 s. If I set the camera shutter to mechanical, the time between shutter "open" and "close" feels longer than the shutter is reacting. An using AF-ON makes also a difference when in AF-C mode, because the camera already catched a target before I press the shutter. In any way, it really doesn't matter that much: If the lab which was measuring the times chose a good enough setup (I think of lights on DC or AC current, with lens or without and if with: with which lens?)

Also Tony Northrup's (who was wrong in the past and has some opinions I not necessarily agreee with) video put at the moment of the "shutter lag numbers are..." a text balloon to his mouth saying "in AF-C". AF-C can be a lot these days: With/without face detection? eye-AF? animal or human eye? object tracking? how big the AF-zone? and lastly how good the lights and how fast the lens...

That value might be accurate for one single test situation, that situation will happen statically so the meaning to camera's behaviour in real life is zilch or very close to it. What also comes in my mind: Nikon states in their manual to only use AF-fine-tuning if one has to, otherwise it might slow down the AF. How many lenses I have which would allow me to switch the AF fine-tuning results of? Exactly one, the new Sigma 70-200/2.8 Sports was to my surprise perfect out of the box.

Maybe there's not much to read about shutter lag because you get used to it and compensate it by just pushing the button earlier. As EACH camera does have a lag, a photographer already needs to anticipate that delay. No one will ever be able to convince me by saying "with my XY body and a Z-lens I can catch a swallow in flight, while it's looking to the left side, wings spread to the max and catch a bug in mid-air". It can be done - but not on purpose.
#26
Whether or not it's a useless game to measure shutter-lag or not, it has been measured ..... and there it is! .... one has to decide whether its treading on your photographic toes ...... it's obviously not stepped on many peoples!

However, the EVF 120 FPS refresh rate does prick my interest .... would it put me off the A9? ...... Simply yes !! ... following an erratic BIF around at long FLs is already hard with the OVF's real time ..... seeing an upgraded image every 1/120 sec ( including the inevitable time it takes to show in the finder) is not an advantage.

With the Olympic games coming up in July next year and Sony's intentions to bring to the market the replacement for the A9, I would be highly surprised if they didn't address this shortcoming by simply upping the EVF frame rate to 240 FPS (or maybe 180 Fps would do)

I underline that this is a super niche issue and most will never ever notice any of it ...... however, those long lenses with tele-converters at the Olympics may well encounter some of it !!
So my guess is that Sony are already on the case for the A10!
Dave's clichés
#27
That's this cool thing on the internet: One who never ever tried a mirrorless + long lens + extender knows everything what's needed to suggest the manufacturer a shutter lag/refresh rate of the EVF to his needs although he never will buy an α9 or α10.

Tony Northrup was wrong in the past, here maybe as well by constructing a use case which I never found to be troublesome. I suspect, his camera was set to a lower EVF refresh rate. He was machinegunning, so the shutter lag doesn't matter at all. And I still wonder why he (who is not known as a bird photographer) finds so many problems whereas Mark Smith appears to change between DLSR and mirrorless α9 without any troubles?

One note in the manual says " During blackout-free shooting, the slower the shutter speed, the lower the refresh rate of the screen. If you want the screen display to be smooth in order to track the subject, set a shutter speed faster than 1/125 second." (but that's for silent shutter, I could not find any data about the refresh rate)

Refresh rate apart: how safe and accurate can you shoot when using the monopod setting of Northrup and being on a boat, with a 1200/8 lens? How often are you using a 600 mm with TC? If the pictures of the flying bird were done with this combination, the bird was 1/4 mile away and the quality was rather low. No tele ever will be as good as getting close to the bird. And although I own a TC 1.7 II and a TC 2.0 III, I'm no fan of these rather expensive devices.

Don't get me wrong, dave, I don't want to defend Sony but I question the conclusions of Northrup once again.
#28
I take all you say on board JoJu...... but this is not a Tony Northrup issue .... other than it was he who spotted the problem ..... while he was testing the 600mm F4 with a 2x converter.

How can Tony be mistaken? ........ in fact he did well to spot it.

.......... the A9 is behaving exactly as per specifications !! ....... how could it behave any other way?
Dave's clichés
#29
I think I need to review Tony's video. Or maybe not. 

I'm not a dedicated birder, and I will not own an α9 or α10 any time soon in the future, and especially I will never own a combination of a Sony 600/4 + 2× Extender. Therefore the whole combination is as unknown to me as it was to Mr. Northrup. 

I'm just not showing off my lack of knowledge in a YT video... So feel free to arouse yourself with "slow" refresh rates (without knowing how fast 120 Hz really are in real life conditions).
#30
I reviewed the Northrup video. And another one, "maintenance of your gear" in which he used the same brush for lens glass, camera and tripod surfaces - good luck.

In the α9-video I see more pros than cons for the camera, like "more sharp shots than you'd get with a D5 or EOS1". I think at the end of the day this matters much more.

You might be more experienced than I am, but with continuous 9fps and an OVF blackout I find it also hard to track a bird. That was the reason to get the "Dot Sight DF-M1", but this has other disadvantages, like calibrating every time I change a lens and being rather fragile. Best is, one eye open to "track the bird without blackout" and one eye for the finder to check a bit what's going on.

While tracking a bird in flight, I do have a lot of other things to care about than just shutter lag. I'm sorry, but I still find this "shutter lag" a blown up problem - the D5 has half the time, is also lagging, plus restricted focus area and only focusing when the mirror is up again. If I had to choose between a D5 + 600/4 and an α9 + 600/4, I'd always go for the Sony.

What Tony didn't mention, but matters to me: The D5 I could put on a tripod, being in a hide and watch the bird for hours without draining batteries. How long could I do this with an α9, before the heat sensor shuts the camera down or the 3 batteries become empty?
  


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