RETRA Strobe Thread

Or, maybe a few of these?

https://www.amazon.com/Ranger-Bands-Large-20-Count/dp/B079NQWQK5/ref=sxts_sxwds-bia-wc1_0

32 minutes ago, TimG said:

Bermaglot, how do you find the Retra aiming light (the pilot light) when using the LSD? Did you find the strobe light the area illuminated by the pilot light reasonably accurately? 

Aiming light seemed to match the strobe output. I didn't get any shots worth posting, but this was my first (and so far only) dive using a snoot, so that's to be expected.

23 minutes ago, stuartv said:

The price just keeps going up. $1050 for the strobe. $200 for a battery pack? $50 for bumpers? More for the front protector thingie? Fortunately, I think I saw that the neoprene sleeve comes with it.

Unless something changed, the neoprene jackets are a separate item, costing €35 each, while bumpers cost €49 on top of that.

17 minutes ago, deepadrenalin said:

What about double-sided adhesive tape to fix it? 

Interesting idea; haven't thought about that. It might be counterproductive though - the purpose of jackets is to protect the cosmetic condition of the strobe, retaining more of its value in case it ever needs to be resold, while sticky tape strong enough to stand up to salt water will likely leave its own residue on the strobe.

I just did a quick test - just over a second at 1/4 power (25%) and about one second at 12%. I said one thousand to do the timing. Used black Eneloops. There are 2 power settings for the aiming light.

15 hours ago, Barmaglot said:

Aiming light seemed to match the strobe output. I didn't get any shots worth posting, but this was my first (and so far only) dive using a snoot, so that's to be expected.

Thanks! Yep, snooting is not the easiest of arts for sure! But you can certainly get some spectacular images.

Recycle times?

I was just emailing with one of my usual online retailers about possibly buying a pair of Retra Pros, so that I can relegate my Z240s to backup duty.

When I asked about the Pros, they said "the biggest trade offs are they are slow recyclers. About 5 seconds recycle at full power with freshly charged high output batteries."

Okay, 5 seconds for a full dump means 5 seconds after putting out way more light than my Z240s, right? The 240s cycle a lot more quickly than 5 seconds - but they don't put out nearly as much light, I don't think.

What I would like to know is, if I set my Z240s to an output level of f/4 (how the knob on them is labeled), and I set the Retra Pros to output the same amount of light (i.e. to get the same exposure), how quickly will the Pros cycle, compared to the 240s? (assuming they are both loaded with Eneloop Pros) And how quickly if the Retras have the battery extension pack?

Every cycle time spec I see talks about at full power, or at some percentage of full power. That really does not tell me anything. Cycle time at 25% output for a Retra Pro means it's putting out more light than 25% output from a Retra Prime or 25% from an Inon Z240. And if they're putting out light for a different exposure, comparing the cycle time is useless.

2 hours ago, stuartv said:

Every cycle time spec I see talks about at full power, or at some percentage of full power. That really does not tell me anything. Cycle time at 25% output for a Retra Pro means it's putting out more light than 25% output from a Retra Prime or 25% from an Inon Z240. And if they're putting out light for a different exposure, comparing the cycle time is useless.

That's about right, we need at least the energy in Ws or J to determine the speed of recycling. As correctly assumed the PRO's have much more energy in their capacitors compared to Z-240. Also please note that recycle time specs are not consistent, especially with Inon, as was pointed out in this thread here: https://wetpixel.com/forums/index.php?/topic/63538-inon-z-330-ready-light-comes-on-early/

We are on the way to introduce a "Supercharger" for the Retra Flash Prime/PRO that will be an additional battery pack. With it the recycle time for the PRO be halved and the total number of flashes will double. More details will be revealed in the coming weeks when the product is ready for announcement. 

@stuartv Non-scientific comparison: I have both 2 (new) Retra Pro's, and 2 Inon Z330's - at this point I was hoping to have shot with both on a trip but those plans changed with the current pandemic.

Using a fairly unscientific process, I'm fairly certain that I will not be shooting W/A with my Z-330's anymore. I've tested shooting with both in my pool, and the Retra Pro's are both more even in lighting (to my eye) and light up a greater amount of any scene I was shooting than the Z330's.

Shooting several smaller objects (set up for macro) the difference is much less obvious. If I was shooting virtually all macro I would have to start thinking about things like strobe weight, edge lighting, ergonomics, etc. to decide which I might prefer. 

If I could only carry 2 strobes with me I would want the Retra Pro's - mainly because of the flexibility to handle lighting multiple different types of scenes. However, having shot with Inon strobes for years it is taking me a little time to get used to the ergonomics of other strobes. Not a negative - just something I've noticed when in the pool.

10 hours ago, stuartv said:

.... The 240s cycle a lot more quickly than 5 seconds ...

In reality, Z240  charges 52 joule energy (from zero to Full) in 7-10 seconds. Yes, the "Ready" indicator lights after 2 seconds, this value is written in Specifications, but user has to understand  that strobe gets just a partial charge in this time. The 2 seconds is usually a marketing value for this class of strobes, it refers to accepted energy level (50%, 60%, 70% or other, - but concrete level usually is not specified in Specifications).

8 hours ago, Oskar@RetraUWT said:

We are on the way to introduce a "Supercharger" for the Retra Flash Prime/PRO that will be an additional battery pack. With it the recycle time for the PRO be halved and the total number of flashes will double. More details will be revealed in the coming weeks when the product is ready for announcement. 

Are you talking about the additional battery compartment, like is shown here:

https://www.bluewaterphotostore.com/retra-additional-battery-compartment

Also, thank you for that link about Z330 cycle times. I will go and have a read.

5 hours ago, oneyellowtang said:

@stuartv Non-scientific comparison: I have both 2 (new) Retra Pro's, and 2 Inon Z330's - at this point I was hoping to have shot with both on a trip but those plans changed with the current pandemic.

Thank you for taking the time to reply. What I really want to know about is how cycle times compare at "normal" output levels.

2 hours ago, Pavel Kolpakov said:

In reality, Z240  charges 52 joule energy (from zero to Full) in 7-10 seconds. Yes, the "Ready" indicator lights after 2 seconds, this value is written in Specifications, but user has to understand  that strobe gets just a partial charge in this time. The 2 seconds is usually a marketing value for this class of strobes, it refers to accepted energy level (50%, 60%, 70% or other, - but concrete level usually is not specified in Specifications).

Thank you for the details, Pavel. I am starting to have the impression that the cycle time on any strobe is really going to just depend on the batteries used. I.e. the difference in cycle time between any 2 strobes (that both have the same batteries) is going to depend on the specifics of the design, but will likely be very similar.

However, the "specifics of the design" leads me to my next question. I had this additional info from the guy I was talking to at my Retra dealer.

Quote

The Retras also have to fight the slow discharge time of using a long circular flash tube - these take longer to fire than a short straight flash tube. Inons fire at 1/1000 of a second at full power and faster at lower power. And Ikelite fires at longer than 1/200. The Retra is closer to the Ikelite than the Inon. The old Retras where noticeably slower recycling than the Inons at the same power - particularly as battery charge went down. For whatever reason, batteries at even 3/4 charge made the Retra recycle times double and eventually triple, while the same charge on an Inon had almost no effect. So if your primary goal is speed of recycling, then I would ask yourself if you are OK with the 8 battery concept, because that is what it will take to get faster recycle times than a Z-330.

Any thoughts on any of that?

Does the Retra tube take longer to fire? If so, can it handle a 1/250 shutter speed without having to go into HSS? Meaning, can it do a full dump during a 1/250 shutter release?

Does the Retra cycle time slow down a lot when the batteries get down to 3/4 or 1/2 charge?

1 hour ago, stuartv said:

Inons fire at 1/1000 of a second at full power

This depends on the specific Inon. Z-330 has been measured to fire for about 1/300s at full power.

3 hours ago, stuartv said:

Does the Retra cycle time slow down a lot when the batteries get down to 3/4 or 1/2 charge?

My sales guy clarified that he was talking about the behavior of the original Retras on this. He is not sure how the Prime/Pro does. 

Anyone have any experience with this? Does the Retra Pro cycle time slow down significantly when the batteries are down to 1/2 charge?

In reality, Z240  charges 52 joule energy (from zero to Full) in 7-10 seconds. Yes, the "Ready" indicator lights after 2 seconds, this value is written in Specifications, but user has to understand  that strobe gets just a partial charge in this time. The 2 seconds is usually a marketing value for this class of strobes, it refers to accepted energy level (50%, 60%, 70% or other, - but concrete level usually is not specified in Specifications).

2 minutes ago, Nicool said:

Hi Pavel, that gets me confused.
From a user perspective, what matters is: « how quickly do i have sufficient charge so that the next photo is exposed like the previous one (assuming no setting changes) »
If what you’re saying is true with my Inons, i would get varying levels of exposure between shots, whereas i do get good consistency (noting i never shoot them at more than half power, too concerned about overheating).


Envoyé de mon iPhone en utilisant Tapatalk

How do you figure that? He is saying that the Inons recharge to something like 50 or more percent by the time the light comes on. And that is after a full dump.

If you are shooting at half power or less, then you should be able to shoot a second shot instantly after shooting your first shot. If the strobe starts fully charged and you shoot at half power, then wait for the light, it will charge up to something like 80% or more when the light comes on. Another shot at 50% power, will still be fully exposed. And etc..

On 3/31/2020 at 7:22 AM, Nicool said:

Hi Pavel, that gets me confused.
From a user perspective, what matters is: « how quickly do i have sufficient charge so that the next photo is exposed like the previous one (assuming no setting changes) »
If what you’re saying is true with my Inons, i would get varying levels of exposure between shots, whereas i do get good consistency (noting i never shoot them at more than half power, too concerned about overheating).


Envoyé de mon iPhone en utilisant Tapatalk

Hi Nicolas,

You get consistent exposures from your INONS because the output in lumens from a strobe is constant and the exposure is adjusted by the duration of the pulse.  So if you shoot at say 1/4 power, it takes about 25% of the stored energy to power the pulse give or take - assuming 100% of the capacitor is required for a full dump - there may still be some charge left if the strobe uses timing for a full dump.  This 25% dump is 25% of the duration of a full dump.

You are then at 75% and to get to 80% or where-ever the ready light turns on (set by voltage) does not take long.  You shoot again and you have 80% -25% = 65%.  If you keep doing this eventually you will empty the capacitor if you shoot too fast.  A long as the capacitor has enough energy stored to power the strobe tube for the required time the exposure will stay the same.    I'll use a value of 80% - it might be a different number........

If you use full power you may get some variation as the capacitor may take time to completely fill and may not have enough stored energy for a full dump for some time after the ready light comes on.  The charging of the capacitor is initially rapid and slows as it fills so it can get 80%(or ready light on)  in 2 seconds and takes the additional 5-8 seconds to put in the last 20%.

The strobe may have a voltage below which it won't attempt to flash and it won't do so again until it has enough capacitor charge to exceed that voltage. 

The 2 second time to 80% and the ready light probably does have some marketing component, but it also tells you when it's ready to deliver anything less than an 80% pulse, which is what many users will require as they use half a stop or more less than full power much of the time.

Has anyone got the in-water weight of the new Retra strobes? I can't see this on the Retra website. The Prime weighs 750 gms above water and the Pro 790 gms.

I was trying to see what difference the Retra would make to my system buoyancy with the switch from Inon Z20 strobes.

The Inon weighed 580gms above water but only 77 gms in-water.

[.... and that's another session of How To Send Time During Social-Distancing]

Just added "wet weight" information into the tech-spec's here: https://www.retra-uwt.com/pages/retra-flash

3 hours ago, TimG said:

Has anyone got the in-water weight of the new Retra strobes? I can't see this on the Retra website. The Prime weighs 750 gms above water and the Pro 790 gms.

I was trying to see what difference the Retra would make to my system buoyancy with the switch from Inon Z20 strobes.

The Inon weighed 580gms above water but only 77 gms in-water.

[.... and that's another session of How To Send Time During Social-Distancing]

 

I don't have access to salt water right now, but for Retra Pro in fresh water, I get about 190g negative with 4x Eneloop Pro batteries inside, ~90-100g negative with neoprene jacket. Dry weight with batteries is ~900-910g.

2 hours ago, Oskar@RetraUWT said:

Just added "wet weight" information into the tech-spec's here: https://www.retra-uwt.com/pages/retra-flash

Oh brilliant! Thanks, Oskar

1 hour ago, Barmaglot said:

I don't have access to salt water right now, but for Retra Pro in fresh water, I get about 190g negative with 4x Eneloop Pro batteries inside, ~90-100g negative with neoprene jacket. Dry weight with batteries is ~900-910g.

Terrific - many thanks!

That's really helpful especially with those cute little jackets 

So, in theory, if you move from an Inon Z240 strobe to a Retra Prime (with neoprene jacket) you add approx  ~23gms of buoyancy.

By my calculations that is less than half a Jumbo-sized Stix float per Retra strobe