Mx10 & Ys40a

[herman]

Seeing the photos would help but I suspect you are asking the camera to do something it is not well suited to do. With no shutter speed control you have 2 choices, shoot within the range of the strobe (+- 4ft) and accept dark backrounds or shoot in high light conditions, something most pools are not. Your best bet is to stick to close in shots and accept the dark backrounds. The camera is very capable of taking good photos at closeup and macro distances. The close up and macro lens work very well.
I have tried using a higher speed film at the lower speed setting with some success but you risk over exposing the near field if you do. It would take some testing to get the setting correct and then it's unlikely you will get the results you want. With the cost of film and processing I am not too sure it's worth the effort. The testing cost would soon be as much as an inexpensive digital setup.

 

[benze]

Thanks for the reply. I wouldn't be surprised if I was asking the camera to do something that it wasn't suited to do. I am completely new to both the camera and UW photography in general, so could definitely use tips & pointers. I picked up the MX10 b/c I got a good deal on it, so I'm trying to figure out how to use it as best as possible.

I did get both a macro lens and a wide angle lens with the camera. I didn't realize that the closeup and macro lenses were two different lenses; is it worth picking up a closeup lens as well? I can get one for about $45, but don't know if it is worth the extra cost. I'm not too sure how useful the macro lens is for taking pictures of things I see while I am diving, vs. diving to take specific pictures.

Right now, my biggest concern is that the background looks quite dark, and I am not sure if that is something I should be expecting or not. For instance, in the dive tank, at 50ft, I am able to see the top without too much difficulties, however, the shots have it looking completely black. I have a YS40 (not the YS40A), and I am not sure how much difference the YS40A would make, but I can only imagine that the 40A would help expose the shots better. Does the auto setting on the 40A really help a significant amount?

I am not sure of the fstops I used for the shots (i think I took some at 4 and 5.6), but can't remember to be honest. I uploaded some sample shots to give you an idea of what I am talking about, and the lighting at the different depths. As you can see, at 10ft, there is plenty of light, and that light carries down to the bottom, and yet shots lower down are much darker.

I was running 200ISO film, with the ISO switch set to 400. I don't know if this will make a huge difference, as I don't know if the camera actually calculates a different shutter speed based on the film speed or not.

@ 12ft (plenty of ambient light):
http://www.scubaboard.com/gallery/showphoto.php/photo/66435/cat/500/ppuser/56938

@ 40ft (background is already quite dark):
http://www.scubaboard.com/gallery/showphoto.php/photo/66434/cat/500/ppuser/56938

@50ft (can see the top of the water clearly when diving, but completely dark in the shot)
http://www.scubaboard.com/gallery/showphoto.php/photo/66433/cat/500/ppuser/56938

BTW - all shots are taken in the middle of the day (around 10:30am in the morning) on a sunny day, with windows all around the dive tank, so there we plenty of ambient light everywhere.


Any tips or tricks you can share would be greatly appreciated! As expected, the local libraries I checked for the New Guide to Sea and Sea didn't turn anything up. I am afraid it is too specialized a title to find in Montreal.

Thanks!

Eric

 

[Ronjac]

Hi Eric, Hi Herman,

I hope you wont mind if I share with you what I have learned from the book.

Proper setup of F-stop, shutter speed and film speed controls the amount of light which reaches the film. MX10 is camera with fixed shutter speed at 1/100 seconds and there is no way you can change it. On the other hand, you can change F-stop to control the amount of light, and film speed.

Film speed is a measure of sensitivity of film to light. ISO 400 are sensitive/fast films-they require less amount of light to achive correct exposure than ISO 100. ISO 400 doubles the maximum range of flash over ISO 100 which allows for smaler F-stop, which extends depth of field. In low light conditions, I would try with ISO 400 and would set ISO selector for film speed on 400 as per the book (deep diving, wreck diving).

Macro Systems and Close-up both magnify the subject allowing closer focusing and reducing water column between the lens and subject-good in poor visibility.

MX10 built-in 32 mm lens is good for: head-and shoulders diver portraits, medium size fish, lobster, crabs, sillouettes-you should try this.

MX10 Close-up lens is good for subjects 3-12 inches tall (sea stars, octopus, small to medium fish).

MX10 Macro Lens is designed for images of sea's smaller subjects-up to three inches tall.

Again, I'm novice in U/W photography and I would strongly recommend The New Guide to S & S (Liburdi/Sherman).

Best regards.

 

[herman]

So you got the book, great. It is the best book I have found on the MX-10 and I still go back and read it from time to time, many of the subjects apply to digital as well.

 

[benze]

Thanks so much for the feedback Ronjac. I did find a copy of it on Ebay, and am waiting for it to get shipped to me. Hopefully in time for my dive trip.

Now maybe either you or someone else on this board can aswer the following question for me. It has been driving me nuts. I emailed Sea & Sea, but they haven't been able to provide me with an explanatory response.

The camera has an ISO selector on it. If the camera speed is fixed at 1/100 second, what use is that ISO selector? Under normal circumstances, I would expect the camera to select the speed of the shutter based on the amount of light and the speed of the film. However, if the shutter speed is fixed at 1/100th of a second, what good does that selector switch do? What difference if I set it at either 100 or 400?

Thanks!

Eric

 

[herman]

I need to dig up my book but it has to change the shutter speed, otherwise the exposure would be wrong for a given F-stop.

 

[herman]

Got the answer. The shutter speed is fixed at 1/100. The 100/400 switch changes the calibration of the internal light meter. This changes the F-stop "recommended" by the internal light meter.

 

[benze]

Thanks for the info Herman. That kind of clarifies things a little, but I guess I still don't get it. Given that the f-stop is a manual setting, how am I supposed to know what the "recommended" fstop is? Does this make any difference with respect to the flash? ie: how much power it uses? Or is the flash simply and all-on / all-off flash?

I guess I am still having trouble understanding how changing that switch will effectively change my picture exposure given identical lighting conditions between the two settings.

Any ideas?

Thanks,

Eric

 

[herman]

Lets see if I can clear it up.
There are basically 2 conditions we are dealing with.
First is no flash, strobe or otherwise. The exposure is determined by ambient light, film speed, F-stop and shutter speed. Since ambient light, shutter speed and film speed are fixed (once the film is installed), the only thing we can control is the F-stop....how big a hole that is in the aperture. So how do we determine what the correct F-stop is? We either take a swag or use the internal light meter. You do know the MX-10 has a light meter don't you?? Press the shutter release 1/2 way down and look for a red light in the view finder, if it comes on, you need to open up the aperature (use a LOWER F-stop) until the light does NOT come on. Trouble is, 100 sp film speed takes a different amount of light (2x more) than 400sp. If we only had a light meter calibrated to 100 speed film and if we used 400 speed film, the light meter would indicate we should use 2 F-stops lower than we actually should (a smaller F-stop number is a LARGER hole in the iris...F-4.5 has a bigger hole than F-11), causing the film to be over exposed. The opposite condition, 100 sp film with the light meter set to 400 would indicate an F-stop setting 2 higher that we should, causing the photo to be underexposed. The MX-10 corrects for this problem by giving us an internal light meter that is calibrated to 2 different film speeds. By matching the film speed with the correct light meter calibration we get the correct F-stop recommended by the internal light meter .

Now, the second condition- WITH an external strobe.
The light meter now is pretty much useless because the "light" we are concerned with is no longer the ambient light but the output of the strobe, something we can not measure with the light meter. Our exposure is now controlled by strobe power, shutter speed, F-stop, film speed and a new factor, subject distance. Ambient light does figure into the equation but it's minimal compared to the strobe and we can pretty much ignore it. Again, strobe power, shutter speed and film speed are fixed but we can control F-stop AND distance. The proper F-stop is determined by the distance to your subject. If you look on your strobe it should have a sticker on it giving you the proper distance for a given film speed and F-stop. The closer you are, the larger F-Stop you use (smaller hole). For example with 100 speed film you should use an F-stop of F4.5 at 5.5 feet and an F-Stop of F22 at 1 ft.(and a close up lens because 1 ft is too close for the standard lens) You need the table on the strobe to properly determine the correct F-stop to use at a given distance….or if you like math you can calculate the correct F-stop/distance, too much of a pain for me. J
The above is for the YS-40 or the YS-40A in “on”. The YS-40A in auto mode adjusts the output of the strobe to a preset level. The level is preset to an F-stop of F4.5 for 100 speed film and F8 for 400 speed film. With the YS-40A in auto, just set the F-stop to match the film and shoot.

Is it clear as mud now??
The "New Guide To Sea and Sea" does a real good job of explaining the relationship between the strobe and F-stop.
By the way, do not use the internal flash with the YS-40 underwater. The internal flash is intended for above water use. It will work but it causes more problems than it’s worth.

 

[Ronjac]

Yes, built in light meter, and that’s what I didn’t figure out yet. The book says that when you depress camera shutter halfway, the warning low exposure red light will light up if f-stop is not set correctly for film speed used. In order to determine right exposure we should start with f/22 and keep on depressing shutter halfway and opening the f-stop until we achieve right exposure-the red light doesn’t come on. The problem is that no matter which f-stop I chose, even if I try to “overexpose”, the red light stays on. I understand that this light only warns you about underexposure, but it’s still on when I point the camera towards the 100W light bulb? Could it be that light meter on my camera is not working properly?