stephen_ratzlaff

Wow, that scale didn't turn out right.

How do I edit my post to fix it?

400ws to 1200ws is tripling the power. But remember full stops require doubling the power. So to get a full two stops you'd need 4 times the original power or 1600ws. Double once from 400ws to 800ws, double that 800ws again to 1600ws.

See below.

400ws to 800ws is doubling the power so a full one-stop increase in your meter reading is accurate. Then another doubling of power from 800ws to 1600ws would be needed to get another full stop of power for a full two stops.

But ....in your case, you're going from 400 to 800 which is one full stop and then going from 800ws to 1200ws which is only another 0.5 stops for a total of 1.5 stops. 800ws to 1200ws is only adding another 400ws which is half of what is the needed 800ws to make the 1600ws total.

I hope this is clear. Measuring light is an exponential affair so to speak and not linear.

2 raised to the power of n (2^n) is the scale you need to learn/use/remember.

2^0 = 1

2^1.5 = 1.4

2^1 = 2

2^1.5 = 2.8

2^2 = 4

2^2.5 = 5.6

2^3 = 8

2^3.5 = 11

2^4 = 16

2^4.5 = 22

2^5 = 32

2^5.5 = 45

2^6 = 64

and so on ...

Notice how these match up on your aperture scale and very close on your shutter speed scale too.

I should mention, there is a hole on the opposite side where the screw resides.

loosen the screw, align the white mark with the correct bracket mark, tighten, and then you're good to go.

Easy fix.

The knob has a small hex screw in the back (the opposite side from the white marking).

Just find the correct size hex wrench and tighten and you're good to go.

I have an old Epson Perfection 2450 Photo scanner I use for large format scans.

I'd like to get a dedicated 35mm negative and slide scanner and found the

Plustek OpticFilm 7200 Film Scanner on newegg.

There are a couple of reviews which are positive, but I'd like to know if anyone

here has one and can recommend it for scanning 35mm.

If you mean studio quality strobe battery powered ... you're gonna have to pay quite a bit for this equipment.

OTOH, if you mean small flash battery powered strobe then get a bunch of old Vivitar 283's or 285's and use inexpensive triggers on all but one of them, then use a wireless device like Ellis recommended on the primary flash to trigger it. The primary flash going off will then trigger the others.

The L508, L558 and Minolta Flash Meter VI all go down to f/0.7 or f/1.0 in incident mode.

Not the same thing as reflected spot reading of flash.

Unfortunately, the meter will not read lower light than that in reflected mode.

Sucks don't it.

The 558 is a bit better, and the Minolta Flash Meter VI is better too.

Really, that's the only bad quirk of the 508.

Barebulb -> f16.8

Zoom Reflector at 10 setting -> f16.9

Zoom Reflector at 4 setting -> f32.3

Zoom Reflector at 7 setting -> f22.0

Here's a couple of quick measurements from a Profoto Acute2 2400 pack and single head, with head in A socket and set to full power.

Flash meter and distance: Sekonic L-558 set at ISO 100, shutter speed 1/250th second sync speed and using dome "up" in incident mode at 10 feet from front of flash tube cover.

Barebulb -> f16.8

Zoom Reflector at 10 setting -> f16.9

Zoom Reflector at 4 setting -> f32.3

Zoom Reflector at 7 setting -> f22.0

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Next are measurements with softbox with internal baffle in place.

Softbox used Photoflex Q39 White (i.e. not silver) 36"x48" with internal baffle/diffusor in place.

Flash Meters and distance: Sekonic L-508 and Minolta Flash Meter V both set to ISO 100, 1/250th sec sync speed with dome up on Sekonic and using incident mode on both meters. Meter incident dome placed in center of beam (if you can call using softbox a beam) at 5 feet from the front of the flash tube cover, not the front of the softbox, don't ask why, I can't remember. I think to match the Chimera results so many years ago. If I remember correctly, this is how they measured the light with various heads also. Or ... it could have been the published results Calumet used to have in their paper catalogs years ago. I can't remember, but it did it this way for some reason to match some published readings from somewhere else.

Anyhow, now for the results:

Single head set to full power on pack. Head in socket A on pack.

Full power (i.e. 2400ws/joules on pack) on single head (baretube) in softbox results in f45 on both meters.

I have other readings at lower settings if anyone is interested with the Acute2 flash head and pack set at different settings with the same softbox and same criteria.

BR

Juice

See this post for more info:

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=0084Xk

Anyhow, for my system I've ended up spending a little bit less than what it would have cost to buy the Profoto 7B system with one head. Of course, my system weighs a lot more, and is bigger in size as well.

You can buy the Dyna-Lite XL1100 to power a single pack around 1000-1200ws, so maybe this would be an alternative for you.

My system works fine for powering two Profoto Acute2 2400ws packs with modeling lights OFF, or one pack with modelling light ON dim setting. I can't tell you how long it will run for, but easily 100 full-power pops with single pack and single head and modeling light OFF.

I'm planning on adding another Optima Blue-Top battery to the system. Just for info, my inverter weighs 32 lbs, the single battery weighs 59lbs, so you can see that with two batteries and the inverter the weight is most prohibitive.

Anyhow, I wanted a system I could use for other things when I'm not using it out on location, hence this path.

If you want a light weight system, then the Profoto 7B or Helsel Porty or Elinchrome Ranger? or the Dyna-Lite XL1100 would better choices.

BR

Thomas:

"Also, the next consideration would be to slide a capacitor in between the battery and the power inverter."

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Stephen:

Yep, I'm considering that too.

I'm fairly happy the unit works with both packs at full power (2400ws x 2) simultaneously even with modeling lights on (250w x 2 continuous for two heads).

The alarm merely shows the voltage dropping below my alarm threshold of 10.5v but the voltage doesn't drop below the inverter shutoff of 10.0v. These alarm and shutoff points are completely user configurable so I could lower them a bit if needed to reduce the alarm indications.

But, really, I think I need at least one more battery (maybe two for long shoots).

Good news is the inverter works fine and both packs work fine without modeling lights on. Each modeling light draws more than 6-8 amps continuous DC when on full power. But, I can minimize the power settings for the modeling lights quite a bit from the packs' modeling light settings.

Anyhow, this weekend I'm going to do a torture test (my poor kid will have to model) while I try to run the batttery down while using one pack with modeling light on at lower settings.

I'll keep you posted.

BTW - Xantrex who makes the Prosine and Donrowe.com where I bought the original Prosine 2.0 and then exchanged it for the 3.0 have been great. Both good companies to deal with.

I also found out that Xantrex has a new line of inverters the MS-2000(Marine?) and RS-2000(RV?) in 2000 watts and will be coming out in the future with 3000 watt (12V) and 4000 watt (24V) versions as well. Don't know the time frame of the 3000 or 4000 watt versions, but if they offer serial (connect in serial for 220-240VAC) power like the Prosine 2.0 does then I'll be buying a MS version as well.

Then I'll relegate this Prosine 3.0 to house duty.

I've been planning to use the inverter for house power anyhow and have been running T.V.'s DVD's VCR's and lamps off the 3.0 for the last few days. With a single 75Ah battery I can watch T.V. with two 60 watt lamps on for hours and hardy see the battery voltage drop.

Received the Prosine 3.0 and it WILL fire both packs simultaneously.

However, both packs at full power (2400ws each) do create a bit of strain at the battery, i.e. I need more juice so another battery or three will be in order. ;>}

I can fire both packs with one head each with modeling lights on full but the battery can't supply all the juice I need and voltage drops to a point the inverter alarms. But, the inverter doesn't shut off.

Still everything works which means after adding a couple more batteries I could use both packs.

BTW - I can use both packs on both fast recycle and slow recycle with modeling lights off just fine. I don't know how many pops I can do with this cfg, but I suspect with only one battery not too many.

Anyhow, I will be doing some testing this weekend with one pack with modeling light on at lower settings and the actual strobe power set to full (2400ws) just to see what happens. I'm now curious to see how many pops I can get with one battery with this cfg.

I hoping for something like 200 full power pops with limited modeling light use (modeling light on lower/lowest settngs). The modeling lamps are 250watt so they suck up some real juice, especially when set to full power. Luckily, the Acute2 pack can set the modeling lights to lower power.

BR

The line stating 1.375 further away should read something like 1.375 times (1.375x) away.

Sorry for the confusion.

You don't take the 3 feet and square that, you take the fraction of moving the distance from 8 to 11 feet and square that instead.

Example, 8 feet to 11 feet is not doubling (1/4 stop) or tripling (1/9 stop) the distance.

It is:

11/8 = 1.375, 1.375^2 = 1.89 which is almost 2 so you have a ratio of 1/1.89 which is almost half the light.

Inverse square law states something like double the distance then take the inverse of the ratio and square it. So moving light 2x further away gives you 1/4th the light hitting any given area.

Triple the distance and you get 1/9th

But you aren't doubling or tripling the distance. you're only moving the light 1.375 further away when you move from 8 to 11 feet.

BTW, yes, a quick way to set lighting ratios is to use the f-stop scale and set your lights accordingly, cool huh?

Hope this helps.

BTW, try all the f-stop numbers and relate them to each other this way and you can see they all fall pretty close to 1/2 the light when you move the distances further like above.

Profoto specifically stated no modified sine-wave inverter would work.

Still, I'd like to get a beater pack for cheap and try it on that one first as the modified sine-wave inverters are much cheaper.

BR

I've sent my 2000 watt inverter back to exchange it for the 3000 watt model.

The 2000 watt inverter couldn't handle both packs simultaneously and would immediately shutdown after the first pop of boths packs.

It would handle one pack with modeling luight on however, but I wanted to use both packs.

BTW, the current drawn from the 12v battery while recharging from connecting only one 2400 watt second pack with one head and set to full power (2400ws) was in the neighborhood of 220 amps. Yikes!

Anyhow, I'm hoping the 3000 watt inverter will fair better with both packs.

BR

Flash duration of 1/320th sec is longer than shutter speed duration of 1/500th sec.

Think about it. The shutter isn't staying open for the full duration of the flash pop. The shutter is only staying open for a fraction of the strobe pop.

1/500 is shorter period than 1/320. Take your calculator and divide 1 by 500 then 1 by 320 and you'll see what I'm talking about.

You've mentioned it correctly when you state:

"Since Hassy lenses sync at 1/500, the shutter isn't open for the entire flash at this setting."

Since the shutter isn't open for the full duration of the flash pop, you're going to get less exposure.

About the vignetting, nope, that's not how leaf shutters work. Think about a continuous light source, the Sun, and the fact the shutter when actuating goes from a small hole to a larger hole, then back to a smaller hole when taking a single exposure.

The only thing you'll see is hat you've already seen, less exposure from strobe pop than you'd expected.

If you look at the catch lights in the subjects eyes you can see they exhibit the same problem as those of the wedding picture.

The catch light should have clear/sharp delineation, not a feathered effect like shown on the top and bottom of the catch light unless the light source was purposely this way.

You can also see some ghosting on parts of the flowers/design on the dress.

I'd suggest using the camera in shutter priority mode for a while and not let the shutter fall below 1/60th second or so before blaming the issues on the camera or lens.

If you can set the camera up on a tripod. Use the built-in flash and set the shutter speed to 1/125. Focus clearly on a subject and have your subject sit very still ... AND THEN YOUR SHOTS ARE THIS BAD AFTER DOING THIS, then you probably do have some kind of defect going on.

If you have a front/back focus thing going on then take a couple of shots manually focusing on the eyes of your subject. If these shots are sharp, then at least you know the camera is capable of taking shots which are sharp. Also remember, the focus indicators in the viewfinder are actually slightly larger than the rectangles you see in the viewfinder. You really have to pay close attention to what you're focusing on to determine if you have a front/back focus problem.

The only power connector you need is the 20 pin ATX connector to the MB. The additional 4 pin connector is used for Intel compatible MB's.

The AMD compatible MB's I have don't use or even have a place to plugin the 4 pin connector.

Could be a faulty PS or a faulty MB, either way.

Check all your jumper/dip switch settings etc. to make sure they are correct for your processor and memory if need be.

If you have another ATX MB handy you could try connecting the PS to it, but since you haven't mentioned that, you probably don't have anything else available.

What I'd check carefully is that each pin on the atx connector is fully seated, then I'd check the MB connector and flip the board over to check the solder joints to make sure they are good for the atx connector on the MB.

If all checks out, you'll have to find some way to test the MB and PS individually. You could always buy a cheapy PS locally and try it out against the MB.

Can you close the lid all the way?

This little cart looks like it would be easier to "cart" around thatn what I was thinking of using.

Where'd you get it?

BR

SR

A charger with 3 stage charging would be best. It'll bulk charge, then absorption charge, then float charge. Each stage is done at a different voltage for a different length of time. The float charge is really the last step designed to cap off the battery so it doesn't run down.

That's the only thing I can think of for the battery charger issue you mention.

I'm seeing a slight issue with my inverter, actaully a very minor issue. The LCD backlight on the control panel doesn't turn off when I configure it to do so after a specified period of time. The backlight stays on indefinitely. I'll be calling Xantrex in the morning to see if the problem is with configuration or if the problem is the panel itself.

Anyhow, as for charging and doing the inverter part, the unit works great.

I too, haven't found the "box" to mount everything in yet, but will begin looking this week after taking measurements, etc.

Now charging the battery for the first time with the Prosine 2.0.

Already went through the start-up procedures listed in the manual and everything checks out fine.

Have tested the inverter function with a lamp and works fine.

Will test the inverter with one of my PC systems tomorrow to see if the 16ms switch over time works fine and doesn't cause the PC to reboot.

The after a really good charge will torture test the inverter and battery by running T.V. and sound system to listen for bad harmonics or RFI/EMI (there shouldn't be any with pure sine wave), but want to be sure.

Next, will have to find an enclosure for everything; this is the last step and then I'll have portability.

Once I have the battery and unit safely mounted into its home on wheels, it'll be time for the strobe test, hehehe!

I'll keep you apprised.

BR

SR

Inverter was $1472 and battery (D31M) was $208.

Cart and all the other stuff like cables and tool box, etc. will probably be another $100-125 or so depending on what I decide to use.

Anyhow, I look at it this way. The Profoto battery pack system is over $3000 and I could only use it for taking pictures.

The setup I'm building here, I can use for a variety of things. Computer backup (albeit quite expensive one) or as AC power source during electrical power outages, etc. for T.V or the refrigerator.

I've even thought that maybe I'll purchase another Prosince 2.0 inverter in the future sometime if this setup works out well and use them in series to run 240VAC appliances, if the need arises.

Anyhow, for about the same price as the Profoto 7B setup with a couple of heads I can have two complete 2000watt pure sine wave systems which can be used for a variety of things.

Also, I'm thinking my system will give more bang for the buck, so to speak, in that I should be able to get several hundred pops of the strobe at full power (2400ws) compared to the Profoto 7B.

BR