difference between ev and ttl

[dogatecat]

Sorry still trying to educate myself here —— I've purused the forum and have seen bits and pieces about each of the following strobes but, nothing cleanly explaining the differences and advatages.

So...I'm looking at the:​

Ikelite DS-51 Deluxe Ball Arm Pkg., w/ EV Controller


and


Ikelite DS-51 Deluxe Ball Arm Pkg. w/ TTL Sync Cord for Ikelite

What's the difference between having the EV controller and the TTL Synch Cord?
Are ther performance advantages of one over the other.
And just flat out .. what is an EV controller and a TTL sync (I realize TTL means "true to lense" but, miss the storbe connection there)


thanks.

 

[bladephotog]

The EV (exposure value) controller allows you to manually controll the strobe output power. You can dial the power output up or down. The EV controller has a built in slave and is primarily designed to be used with cameras that don't have a synch port.

TTL (thru the lense) sync means the exposure is metered thru the lens and varied accordingly. You can still use the DS-51 in manual mode with the TTL cord, so it just depends on what kind of camera and housing you have. If you can plug in a synch cord then go with the TTL synch.

 

[RonFrank]

I noticed from your other posts that you may not have purchased a camera yet.

If you plan on using IKE strobes, get a camera with a sync terminal. The Ike EV controllers are bulky, and IMO do not work as well as the optical fiber solutions used by many other manufactures. Sync cords are the most reliable solution to fire a flash, and they can offer features like the manufacture designed flash TTL (iTTL/eTTL for example) that an optical sensor does not.

If you want to get a camera without a sync terminal, than I'd look at INON strobes. They are lightweight, and their STTL (I think that is what it's called) fiber optic connection seems to be one of the best on the market. They also offer more flash modes than Ike Strobes, and every one I've every talked to that is using INON has been very pleased.

For solid scuba camera gear opinions, and solutions, I'd call reef photo. HERE is the link. They carry Inon, Ike, Nexus, Aquatica, Subal, and a ton of high end gear. Ryan (partner) is a great resource, but I think everyone at the shop both shoots, and dives, so they know their junk.

 

[dogatecat]

bladephotog -- thanks for the definitions.

correct... I am still browsing and weighting out my various options.

It's quite impressize how much love reef photo and ryan, in particular, receive across the scubaboard. I will definitely have to get at him with some questions and perhaps purchases.

RonFrank - So, is it the camera itself that requires the sync terminal or the housing or I suppose it would probablt be both?
Can you recommend any off the top of your head?

Currently, since I already own alot of sony accessories (which will help to control costs in the end) I've been concentrating on Sony Cameras.

Advice?

Thanks for all the help

 

[bobf]

I'd like to offer a personal opinion on the use of the Ikelite EV controller along with definitions of INON terms in use.........

The Ike EV manual controller is an extremely reliable piece of equipment (personal experience) that offers 10 steps of manual control (full dump down to -4.5 stops) when attached to an Ike DS series strobe. Very intuitive, very easy to use. And since the controller is positioned close to the housing, very convenient.......much more convenient than having to switch strobe intensity levels otherwise located on the strobe itself, which at times might be at the end of long strobe arms in wide angle use. Since the manual controller is also equipped with an optical sensor, it can be used with or without hard wiring through to the housing bulkhead. When the strobe is optically triggered it makes for one less hole in the housing and also negates one of the weakest links in any underwater system, the sync cord. The EV manual controller has many happy users, including myself.

INON's S-TTL stands for Optical Synchronization TTL. In other words, it relies on an optical sensor to monitor the onboard flash unit of a digicam in order to offer TTL like performance. When set to S-TTL, the INON strobe will mimic the firing and quenching cycle of the onboard flash, which is controlled by the camera's exposure circuitry.

The fiber optic cord system used by INON in conjunction with S-TTL circuitry and their Clear Photo System is called the Optical D Cable and Cap set. The Cap fits over the sensor of the INON strobe, insuring where the strobe will get its optical commands from. The fiber optic cord offers the light coming from the onboard flash (master strobe) a path directly to the sensor on the INON strobe (slave strobe). The Clear Photo System blocks "visible" light emanating from the onboard flash from bouncing around inside the housing. It also cuts down the chances of capturing backscatter caused by the onboard flash.

Besides full manual and S-TTL modes, some INON strobes are also equipped with External Auto mode, which in essence is a variation of manual mode control, imho. The user matches the aperture setting on the strobe with the aperture setting on the camera. In external auto mode the strobe must also be aimed directly at the target in order for it to receive its reflected light back to its sensor, which is positioned on the strobe head.

All the options available with both camera and strobe can certainly add to the confusion of "what is best". I agree that your next step should be a conversation with a full service underwater photography specialty shop such as Reef Photo.

 

[alcina]

Again - thanks so much for the clear and helpful information, bobf. I have added the above post to the Pink Link unders "strobes", which is post #5 in the Pink Link.

 

[RonFrank]

It's quite impressize how much love reef photo and ryan, in particular, receive across the scubaboard. I will definitely have to get at him with some questions and perhaps purchases.

RonFrank - So, is it the camera itself that requires the sync terminal or the housing or I suppose it would probablt be both?
Can you recommend any off the top of your head?

Ryan gets press because he is a helpful dude who has access to more stuff than most, and he knows how it all fits together. Personally I never thought I'd need much advice about anything photo, that was until I stepped into the world of UW camera equipment where nothing is standard, and everything is unique.

The camera requires a sync terminal to work with a sync cord. BobF feels that Ike's EV solution is good. I would suggest to get the manual controller as the TTL controller does NOT have multiple options to control the flash.

PnS camera with sync terminals are becoming a thing of the past with low cost DSLR's available, but the Oly SP-350, and the Canon G7 both are high end PnS options with sync terminals. Actually IMO a low end DSLR maybe a better way to go.

 

[bobf]

Kristin,

Not to steal this thread but Congrats to you and Dave!!!!!

Ron,

It certainly does appear that PnS cameras with hot shoes are harder to come by these days. As you point out the Oly SP-350 and Canon G-7 may be the last of a dying breed. Camera companies assume today that people who buy PnS cameras only want to do two things with them...........point and shoot.

Also, I believe Ikelite agrees with your opinion on the choice of the optical EV controller over the optical TTL sensor for most applications, especially with the newest digicams. I was fortunate that my Oly c4040 was one of the last PnS cameras that offered consistent results (except for the inability to fire a full dump in TTL) with the Ike TTL sensor.

Dogatecat,

Sorry to hear about your cat

If your camera of choice is equipped with a hot shoe and you choose a strobe with a sync cord, then inside your underwater housing you will find a set of wires that connect the camera's hot shoe to the housing bulkhead. Outside of the housing, the bulkhead is connected to the external strobe with a sync cord.

In TTL metering, the camera dictates to the strobe when to turn on and off. With dSLR's sometimes fire and quench commands are repeated numerous times, pre-flashes milliseconds apart, followed by the main flash in sync with the shutter event. The electric trigger and quench signals are sent from the camera to the hot shoe where under normal conditions you would find the flash unit. Inside the underwater housing however the flash unit is replaced with a hot shoe connector and set of wires that are connected to bulkhead. The electronic commands pass through the hot shoe connector, through the set of wires, through to the bulkhead, onto the sync cord and then finally to the external strobe. Care must be taken to insure the sync cord is not damaged by water or physical bending. Care must also be taken when inserting the pins of the sync cord into the bulkhead.

Obviously sync cords are not impossible to maintain. In fact they are the standard for underwater dSLR use. But very prudent divers take backup sync cords whenever they go on exotic vacations.

Strobes may also be operated manually (user defines strobe intensity) with a sync cord. The electronic signal to fire will still come from the camera, this time in sync with the shutter event. In manual strobe operation the user will set the strobe to fire for a predetermined amount of time (similar to EV controller use).

It should also be pointed out that one advantage of a sync cord over an optically triggered strobe is that the camera's battery charge will last longer due to the fact that none of its energy is wasted on firing an onboard flash that's sole purpose is only to optically trigger a slave strobe.

As you can see, more pros and cons............

 

[dogatecat]

Dogatecat,

Sorry to hear about your cat

Funny! ... It's ok though, dog coughed her back up.