Sony NEX 5N and TTL strobe overexposed pictures

[simonknee]

little little

?

Could be the case Interceptor, could be. However since the OP is new to this kit (and UW Photography) I suspect he doesn't know the basic strobe-up-yer-lens test to verify TTL. No point digging deeper until basic functionality is confirmed.

---------- Post Merged at 03:21 PM ---------- Previous Post was at 03:17 PM ----------

Hang on Interceptor, would a NEX in AUTO really increase it's ISO when in flash ON mode ??? Surely Sony wouldn't be that daft!

 

[Interceptor121]

Little light. Yes the camera would do that starting with widest aperture and shutter at 1/60 will then increase ISO right away
It assumes 2 fstops for the strobe usually which means if it is dark easily gets to ISO 400+ that washes your pictures out

 

[simonknee]

McSmarte:

reading your posts a bit more, I think you are trying to combine too many techniques at once.
Basic rule is flash OR red filter, not both.
Having a flash will restore the "missing" red so a filter would just bugger it up again (might look funky mind)!

Both methods take practice so choose one and stick with it for a bit - at least for the duration of one dive
You will probably find the red filter technique easier to start with but it's up to you.
Buy a good book - for me it was The Underwater Photographer: Amazon.co.uk: Martin Edge: Books - and take it with you on your trips.

Happy shooting...

---------- Post Merged at 04:05 PM ---------- Previous Post was at 03:51 PM ----------

Little light. Yes the camera would do that starting with widest aperture and shutter at 1/60 will then increase ISO right away
It assumes 2 fstops for the strobe usually which means if it is dark easily gets to ISO 400+ that washes your pictures out

Hmmmm, well I suppose I never run in Auto ISO, above or below water, so have never experienced this (and my Olympus DSLR doesn't have the huge ISO of modern cameras so it's probably a none issue). Dumb behavior if you ask me, I turn on flash to illuminate the scene, why then have high ISO? I remain skeptical but you've obviously experienced this so I should do some tests with YS-01 flash and high (800-1600) ISO tomorrow.

 

[Interceptor121]

It can happen when you use an external strobe as the power is much more than the internal one by the time TTL realises the picture is already washed out
It would not happen only with the internal flash
Anyway it would be useful to see those picture and check the exif values otherwise those are just wild guesses

 

[rwe]

Have ISO at the minimum and aperture closed shutter speed 1/250 or 1/500 in manual
The camera should still provide ttl
If the ISO is set high it will always over expose

I have an NEX-5N and I believe the max. sync speed is 1/160.

Since I had got my NEX just before leaving for Cozumel, I shot a lot in P mode with flash in TTL although I generally shot in manual mode with flash in TTL with my previous camera. Usually ISO 200-400 for distance shots and 100 for closeup, 1/100 or 1/125 sec. I have an Inon 240Z strobe and didn't have much problem with overexposure but did dial in some negative bias for distance shots in bright sunlight. Also, make sure you have flash in rear curtain mode. You can see some of my shots and the settings the camera chose in P mode here: Flickr: rwe0207's Photostream . Click on picture and then click on Sony NEX-5N at upper right and it will show all the camera settings. In general, when I go back to manual mode next trip I will likely pick slightly higher aperture settings than the camera typically chose because I like a lot depth of field although many photographers don't.

 

[Interceptor121]

I have an NEX-5N and I believe the max. sync speed is 1/160.

.

You are right, still the shutter speed only controls the background not the exposure of the subject. ISO for Macro should be at minimum level, shutter speed at the fastest setting to avoid shutter shake. Aperture highest number possible for max depth of field, widest for bokeh.
In any case what controls the subject exposure if the Strobe TTL, the suggestion of first and second I don't think is that relevant in this case.
But still we need to see what is going on with the pics of the op so we need to see the exif info

Although Sea and sea does not report any information on compatibility of Sony NEX series SEA&SEA |
I am aware store suggest the YS-D1 so it should work

 

[simonknee]

Playing with my YS-01 and Olympus E520 this morning. The way the Oly Auto ISO works is that with flash on the ISO goes to 100 regardless. With flash off the camera picks a suitable ISO for the exposure (within the bounds of a menu settable High Limit). So my Oly wouldn't bugger with the ISO in flash mode but as you say, Intercepter, we need to see the OPs exif data to get a handle on what his NEX has done.

My test was in a very dim bedroom shooting white objects at 20cm with a macro 50mm f2 lens (100mm equiv) on a white bedsheet (I thought this was as challenging as I could make it).

I first tried with the built in flash (the shutter goes to 1/100 when flash is on in Auto/P/A modes).

F2, 1/100, ISO100, Auto Flash - white out.
F2.5, 1/100, ISO100, Auto Flash - blown highlights
F3.2, 1/100, ISO100, Auto Flash - no over exposure above this F-stop

Then with the YS-01

F2, 1/100, ISO100, TTL max - white out.
F4, 1/100, ISO100, TTL max - blown highlights
F5.6, 1/100, ISO100, TTL max - no over exposure above this F-stop and exposes all the way to F22

So the YS-01 on full power contributes nearly a 2 stops difference to the point at which you will blow the highlights. I did some further tests, reducing the flash power control (Sea and Sea say that in TTL mode this is dimming the flash) At the half power mark (two clicks off max on the YS-01 control) the results became like the set from the built-in flash. At 1/4 power it became very dim so I upped the ISO by two stops to 400 and again got the same result. So it seems that going half power reduces the blow out point by 2 stops and at 1/4 power another 2 stops.

It is important to note that I was only testing for the point of blown highlights. Once I had reduced either the aperture or the flash power or the ISO enough to prevent the over-exposure then there was no further difference (i.e. it didn't get darker and darker) because the camera and the strobe were working in optical TTL unison to expose correctly. Which is what the OP wants of course.

Of course this is a different body and lens to the OP and it wasn't done underwater but I felt I educated myself a little and the results might help diagnose what is happening with the OPs shots.

Simon