How to use slow sync on Dynax 5? + Film qn

[TME]

That's precisely what is intended, the ambient exposure should be AE-locked on the background.



Let's see this in 2 parts. Camera is metered for background (shutter/aperture is set for correct exposure of background).

Point of focus is however on a person and this subject fills a considerable portion of the frame.(more than a 1/3). The camera then attempts to allocated a greater weightage of flash output control to the TTL sensor that is near the object at point of focus.

When the flash fires, the flash exposure is adjusted only for light that is reflected from the film plane onto the TTL sensor and typically, the one that receives the most light will be given highest priority to avoid blowout. Distance of subject to background is not an issue here, the more important thing is distance of subject to camera.

Under these circumstances, bearing in mind that shutter speeds are already rather high and that FPsync(greatly reduces usable guide number) is being used, there is very little chance of overexposure.

In any case, a normal camera with an autoflash works perfectly using the above method for daylight fill flash(-1ev). So I think there isn't much chance for a TTL based system to misbehave too badly.

I'm pretty confused...........

U mean to say that our camera's TTL sensors are tied to the focus sensor? I always thought it was tied to the exposure settings... in my understanding, if u use evaluative/weighted average metering and the background is substantially brighter than the subject (which is often the case in bright sunlight), then the camera will expose for the background and the TTL sensors will fire at a lower power due to the high ambient light condition..... this leads to correctly exposed background but a dark/black subject.....

But u seem to be saying that in the scenario I painted, the camera meters the background due to higher ambient light from the bright background (as before) while the TTL sensor will meter for the area that the focus is locked on using whichever focus sensor.... is this right? Cos it does not seem to happen for me...... could u read through what i do and point out where it might have gone wrong?

I dun know if I understood u correctly but this is what happens when I shoot under the same condition that I described: There are 2 different ways with 2 very different results..... perhaps u can explain to me what is happening in light of the discussion u had with forbytes..... all shooting done with a TTL Minolta flash without HSS (basically a 3500xi on a Dynax 7)

(1) If I want to shoot a subject to the left of my viewfinder with flash on, I use the left focus spot on the subject and then depress the shutter button halfway... the camera focuses and meters. In this case, I nearly always end up with a underexposed subject cos the camera's evaluative metering system or weighted average metering system (which ever mode I choose) gets fooled by the bright background light........

(2) But if I choose to spot meter the same subject to the left of the same frame, with the flash on, I use the centre focus spot (no choice) then recompose and then shoot.... this of course forces the camera into slow sync mode. Now if the shutter speed drops to a value that is withn the 1/125 limit (no HSS remember), I get a correctly exposed subject with a slightly overblown background (about 1 stop in my guesstimation). If the shutter speed is above the 1/125 limit, my subject is underexposed but not as badly as in the (1) (about 1/2-2/3 stop in my guesstimation). Basically only part of my flash burst (if any at all) gets caught in the film but the lower shutter speed (compared to without slow sync) I think helps with a more decent exposure.....

I understand also that u can compensate by dialing some overexposure..... but as my lens have limited f/stops (like f/5.6 at 135mm on Tamron zoom), if I want a bokeh look, I might be at the limit of my f/stops and ading +3EV is not going help...... cos u can't open up the aperture beyond f/5.6....... so I spot meter to get around the problem........

I hope u understand me and I am coherent......... kekeke......... I'm trying very hard to understand flash photography......... I'm very bad at getting good exposures when the ambient light from the background and subject are very different............

Thanks a lot!

 

[forbytes]

>I'm pretty confused...........

U mean to say that our camera's TTL sensors are tied to the focus sensor?

No, they are different. TTL sensors takes the exposure reading at film plane. Focus sensor also at film plane but are physically nearer to the viewfinder area. Note that you cannot AF when the mirror flips-up but the TTL works once mirror flips-up. Hope I get this right.

> I always thought it was tied to the exposure settings... in my understanding, if u use evaluative/weighted average metering and the background is substantially brighter than the subject (which is often the case in bright sunlight), then the camera will expose for the background and the TTL sensors will fire at a lower power due to the high ambient light condition..... this leads to correctly exposed background but a dark/black subject.....

Whether the flash still fires at high or low power due to high ambient light depends on the guide number of the flash and the distance of the background. Flash light suffers light fall off which means that the effect of flash reduces as the distance goes further. So if the distance is far, the flash may still fires at full power. by the time the flash reaches that distance, the effect of the flash will be small.

Such problems occurs typically when I try to focus hold and recompose. This problem more apparent in my 505si then Dynax 7. When I hold and shift, sometimes I did not realised that the focus also a little shift and exposure reading re-taken. If you do not shift, this should not be a problem.

> But u seem to be saying that in the scenario I painted, the camera meters the background due to higher ambient light from the bright background (as before) while the TTL sensor will meter for the area that the focus is locked on using whichever focus sensor.... is this right? Cos it does not seem to happen for me...... could u read through what i do and point out where it might have gone wrong?

To simplify the case, assume you do not shift. the camera does not meter the background light but measuring the ambient reflected light from the subject. TTL sensor cannot be locked onto something. It works when flash is fired. To balance the picture, TTL sensor already knows that the subject is dark and require "certain" amount of light to balance the picture based on your metering. it will cut off the flash when the metered subject is correctly exposed. In a center weighted metering, if the real subject is small and as Zerstorer mentioned less than 1/3 area, the metering sensor may not be able to identify the existence of a dark subject and the bright backlight overpowers the subject. That is when you have a correctly exposed background with a dark subject.

>I dun know if I understood u correctly but this is what happens when I shoot under the same condition that I described: There are 2 different ways with 2 very different results..... perhaps u can explain to me what is happening in light of the discussion u had with forbytes..... all shooting done with a TTL Minolta flash without HSS (basically a 3500xi on a Dynax 7)

(1) If I want to shoot a subject to the left of my viewfinder with flash on, I use the left focus spot on the subject and then depress the shutter button halfway... the camera focuses and meters. In this case, I nearly always end up with a underexposed subject cos the camera's evaluative metering system or weighted average metering system (which ever mode I choose) gets fooled by the bright background light........

Yes, this will occur. In either case of metering except spot, the brightness weightage given to sides are less then in the center of the viewfinder. You can see the weightage table if you have the dynax 7 broucher.

>(2) But if I choose to spot meter the same subject to the left of the same frame, with the flash on, I use the centre focus spot (no choice) then recompose and then shoot.... this of course forces the camera into slow sync mode. Now if the shutter speed drops to a value that is withn the 1/125 limit (no HSS remember), I get a correctly exposed subject with a slightly overblown background (about 1 stop in my guesstimation). If the shutter speed is above the 1/125 limit, my subject is underexposed but not as badly as in the (1) (about 1/2-2/3 stop in my guesstimation). Basically only part of my flash burst (if any at all) gets caught in the film but the lower shutter speed (compared to without slow sync) I think helps with a more decent exposure.....


Dynax 7 broucher recommends spot metering for such a tight situation. shutter speed at very high say 1/250 and up does not affect the exposure of the subject or any other matter at all. Instead, as you mentioned, part of the flash burst is caught on the film. What you get is a photo with 2 different exposure seperated by a line and not a uniformly subject correct exposure and back ground over a little. You case will be the metering or slow shutter speed and not the high shutter speed.

I understand also that u can compensate by dialing some overexposure..... but as my lens have limited f/stops (like f/5.6 at 135mm on Tamron zoom), if I want a bokeh look, I might be at the limit of my f/stops and ading +3EV is not going help...... cos u can't open up the aperture beyond f/5.6....... so I spot meter to get around the problem........

When you +3EV, you are actually telling the camera to shoot the picture and overexpose by 3EV overall. How the picture will turn out depends on the intensity and brightness of the back light. In fact when you +3EV, you will typically have a slower shutter speed when you reach the wide aperture end of your lens.

If that is a critical shot and you do not know how to balance the shot, you may want to try exposure bracketing.

 

[Zerstorer]

U mean to say that our camera's TTL sensors are tied to the focus sensor?

I meant that the evaluative metering system will take into account the
focus sensor used and allocate a higher weightage to the TTL sensor located in the same region.

(1) If I want to shoot a subject to the left of my viewfinder with flash on, I use the left focus spot on the subject and then depress the shutter button halfway... the camera focuses and meters. In this case, I nearly always end up with a underexposed subject cos the camera's evaluative metering system or weighted average metering system (which ever mode I choose) gets fooled by the bright background light........

In this case it appears that the evaluative/multi-pattern metering system made a wrong guess as to where the subject was, or the subject wasn't fully on a TTL sensor. If the subject is rather small compared to the rest of the frame, this might happen.

(2) But if I choose to spot meter the same subject to the left of the same frame, with the flash on, I use the centre focus spot (no choice) then recompose and then shoot.... this of course forces the camera into slow sync mode. Now if the shutter speed drops to a value that is withn the 1/125 limit (no HSS remember), I get a correctly exposed subject with a slightly overblown background (about 1 stop in my guesstimation). If the shutter speed is above the 1/125 limit, my subject is underexposed but not as badly as in the (1) (about 1/2-2/3 stop in my guesstimation). Basically only part of my flash burst (if any at all) gets caught in the film but the lower shutter speed (compared to without slow sync) I think helps with a more decent exposure.....

If your shutter speed is higher than flash sync I thought the flash won't be allowed to fire?

Anyway, in this case, when you spot meter, the camera is only evaluating your main subject exposure. The background is totally ignored and depending on the lighting it can be overexposed 1 stop, 2 stop, 3 stops...etc.

Personally, I think just using centre weighted on the background, AE lock and then recomposing and firing the flash should normally work. This almost always requires HSS as the lighting contrast is usually very high. Alternatively, if you want to take away all guesswork from the camera, you might want to meter the background in manual mode recompose and just shoot with flash. As I mentioned before, if the subject is reasonably large in the frame, the TTL flash should take care of its proper exposure

 

[TME]

Thanks guys! That was informative........

Zerstorer, the last part about metering the background and letting the TTL sensor take care of the subject is a little counter-intuitive to me cos usually u want to expose the subject correctly and try as best as possible to balance the exposure of the background without getting a complete white-out.... and doing it the way u describe it opens the way to a very real possibility for the camera to be thoroughly fooled by the background lighting........... could u explain how exactly u do it? I.e. the steps. how u frame when u meter and then recompose?
Maybe I write down what I think u mean and then u see if I understood u correctly..... using the same scenario I painted above...... background with subject on left of frame....

Now I use centre-weighted metering and the left focus sensor (Dynax 7, 3500xi TTL flash) and then just depress the shutter button halfway. In this case, the subject is relatively large (suitable for TTL sensor to pick up). Now the metering system will meter for the background, right? And if the camera has a TTL sensor near to the left focus sensor, then the TTL sensor should pick up that my subject on the left is underexposed because my background is too bright? And therefore the flash will fire a burst powerful enough to iluminate my subject such that the reflected light burst matches that of the incoming light from the background. And therefore, I get perfectly exposed background and subject... right? I get my cake and eat it?

As I say, I never get such exposures with the 505si or the Dynax 7..... I thought the TTL metering system just meters through the lens so that it compensates for the loss of light as it passes through the optics.... as compared to metering that is external to the lens (like a sensor on the body).... I have read the Dynax 7 manual a number of times now but I never seem to understand that the metering system works in the manner that u mentioned leh.... and for that matter this is the first time (most likely I'm a frog in the well lar... ) I have read something like this in Clubsnap cos I have ever asked how to expose for subject correctly in bright background....... and everyone tells me to do exposure compensation....... which I dislike cos it is very guesswork...... (and I'm particularly bad at guesstimates)... and in the end to take out the guesswork.... I just spot meter the subject and heck the background...... (which usually works lar.. kekeke.. )...... any comments on my shooting style and how to improve?

Nowadays I usually shoot twice, I do spot metering, then follow up with a +1-2EV lor... I compare the shots on prints and dun see much difference except that I get better detail (if u look real hard) for spot metering..... perhaps on account of slower shutter speed lor.....

 

[Zerstorer]

Zerstorer, the last part about metering the background and letting the TTL sensor take care of the subject is a little counter-intuitive to me cos usually u want to expose the subject correctly and try as best as possible to balance the exposure of the background without getting a complete white-out.... and doing it the way u describe it opens the way to a very real possibility for the camera to be thoroughly fooled by the background lighting...........

How will the camera be fooled if you are using manual settings? Just meter the background for a proper exposure, set the shutter+aperture in manual mode, recompose and focus and fire with flash.(Assuming HSS or within flash sync speed).

In this case the background will NEVER whiteout because the exposure is set for the background and will not change as you are the one who set it. The camera has no part in the decision except acting as a light meter.

Note that when I said TTL sensor, I meant TTL FLASH sensor. This is different from the TTL metering sensors for normal exposure.
http://www.photozone.de/bindex3.html

What you described should work normally, but there is still an element of chance involved such that the subject isn't picked up by the flash TTL sensor. An off center subject is ok, but it must be sufficiently large in the frame.

Note also that nowadays, flash exposure is controlled by the duration of the burst and not actual output power.

I have read the Dynax 7 manual a number of times now but I never seem to understand that the metering system works in the manner that u mentioned leh.... and for that matter this is the first time (most likely I'm a frog in the well lar... ) I have read something like this in Clubsnap cos I have ever asked how to expose for subject correctly in bright background....... and everyone tells me to do exposure compensation.......

That sounds odd, no amount of exposure compensation alone can correctly expose a backlit subject and its background.

What EV compensation does in this case is to just expose the subject properly and let the background blow out. In fact, you will only need to use EV compensation if you are using a not very good Evaluative/Matrix/Multi-pattern metering algorithm that makes a wrong guess as to what is the required scene.(maybe it thinks its a silhouette). No EV compensation will be needed if you use Centre weighted or Spot metering.

To properly expose a backlit subject and its background together requires one to reduce the lighting contrast difference between the 2. This means lighting up the subject by means of either a flash or a reflector(if background isn't too bright). In fact this is documented in my ancient Maxxum 8000i manual as well.

which I dislike cos it is very guesswork...... (and I'm particularly bad at guesstimates)... and in the end to take out the guesswork.... I just spot meter the subject and heck the background...... (which usually works lar.. kekeke.. )...... any comments on my shooting style and how to improve?

Nowadays I usually shoot twice, I do spot metering, then follow up with a +1-2EV lor... I compare the shots on prints and dun see much difference except that I get better detail (if u look real hard) for spot metering..... perhaps on account of slower shutter speed lor.....

You will not see much difference in prints even with a 1EV difference as the photo lab will compensate for any exposure errors!

If you really want to see what you are really taking, you need to either shoot with a digicam or use slides. Using spot metering along with the 2 will enable you to realise how one should actually read a scene.

When one shoots with matrix/multi/evaluative metering in the camera, you can never be sure of what you are going to get because you are allowing the camera to think for you. The resultant output is based on guesswork using the camera's database of a few thousand different types of image content.

 

[TME]

How will the camera be fooled if you are using manual settings? Just meter the background for a proper exposure, set the shutter+aperture in manual mode, recompose and focus and fire with flash.(Assuming HSS or within flash sync speed).

In this case the background will NEVER whiteout because the exposure is set for the background and will not change as you are the one who set it. The camera has no part in the decision except acting as a light meter.

Note that when I said TTL sensor, I meant TTL FLASH sensor. This is different from the TTL metering sensors for normal exposure.
http://www.photozone.de/bindex3.html

What you described should work normally, but there is still an element of chance involved such that the subject isn't picked up by the flash TTL sensor. An off center subject is ok, but it must be sufficiently large in the frame.

Note also that nowadays, flash exposure is controlled by the duration of the burst and not actual output power.


That sounds odd, no amount of exposure compensation alone can correctly expose a backlit subject and its background.

What EV compensation does in this case is to just expose the subject properly and let the background blow out. In fact, you will only need to use EV compensation if you are using a not very good Evaluative/Matrix/Multi-pattern metering algorithm that makes a wrong guess as to what is the required scene.(maybe it thinks its a silhouette). No EV compensation will be needed if you use Centre weighted or Spot metering.

To properly expose a backlit subject and its background together requires one to reduce the lighting contrast difference between the 2. This means lighting up the subject by means of either a flash or a reflector(if background isn't too bright). In fact this is documented in my ancient Maxxum 8000i manual as well.




You will not see much difference in prints even with a 1EV difference as the photo lab will compensate for any exposure errors!

If you really want to see what you are really taking, you need to either shoot with a digicam or use slides. Using spot metering along with the 2 will enable you to realise how one should actually read a scene.

When one shoots with matrix/multi/evaluative metering in the camera, you can never be sure of what you are going to get because you are allowing the camera to think for you. The resultant output is based on guesswork using the camera's database of a few thousand different types of image content.

Oh! Did u mean manual metering and setting? Hmm....... I always use A priority..... manual is foreign to me lar...... never used it before.... so when u meter the background, do u need to use the centre focus spot? Or any focus spot will do?? Or does it matter only when u recompose and shoot?
Cos I was thinking that it might affect the metering if the metering system was tied in with the focus sensors in any way.....

So manual setting eliminates the chance that the camera gets fooled cos the subject is too small? Or it may still be the case whether manual setting or A priority?

Sorry if I sound rather like a broken record..... this is something that I really dun very much about..... thanks a lot for your patient explanations......

 

[iceberg]

Hi
Still trying to get used to my Minolta gear...
What's the difference between ADI and TTL flash? mm... also.. normally when and what do we use?

 

[iceberg]

also.. after reading thru this thread over and over again... i'm still not sure how to shoot an object with a bright background

 

[deslim27]

i'm still not sure how to shoot an object with a bright background

Does Dynax 5 has a center weight metering? If yes, place your subject in the middle.. fire!

Else, use honeycomb metering, increase the exposure compensation by +1 to +2 depends on the brightness of the background.

BTW, may be you can post your previous result here.. its easier to by seeing a 'case study' :think:

 

[deslim27]

What's the difference between ADI and TTL flash? mm... also.. normally when and what do we use?

Simply..

TTL flash is the default flash metering you'll be using on your camera. ADI is a newer feature by minolta to incorporate with TTL in the flash exposure computation. ADI take the distance between the subject and camera into account, therefore it can be used only when a direct flash is applied.

 

[iceberg]

Does Dynax 5 has a center weight metering? If yes, place your subject in the middle.. fire!

Else, use honeycomb metering, increase the exposure compensation by +1 to +2 depends on the brightness of the background.

BTW, may be you can post your previous result here.. its easier to by seeing a 'case study' :think:

i'm not sure on how to use the compensation method.. coz by theory.. if i inc exposure compensation.. from what i understand.. this increases the overall exposure of the whole picture... so there wouldn't be much difference between the object and the bright background as without exposure compensation??

think there's some misconception with my explanation.. mind correcting it??

 

[TME]

i'm not sure on how to use the compensation method.. coz by theory.. if i inc exposure compensation.. from what i understand.. this increases the overall exposure of the whole picture... so there wouldn't be much difference between the object and the bright background as without exposure compensation??

think there's some misconception with my explanation.. mind correcting it??

Well if u are shooting with flash with a bright background and the subject occupies only a small portion of the frame, then the camera will get fooled into think that u are metering for the bright background. What will happen is that the subject will be underexposed. But if the subject is sufficiently large such that flash TTL sensors pick up it up when metering, then the flash will fill in the subject so that the subject is now well-exposed and the background is exposed properly as well..... but u must use either centre-weighted metering or spot-metering...... to be safe then u can dial in +0.5EV for flash compensation. I'm not sure if the Dynax 5 got flash compensation or not tho'....

For the above scenario, if now u want the subject to remain small in the frame but the camera will expose correctly for the bright background and underexpose the subject, u can do exposure compensation. And u are right that in this case, both the subject and background gets overexposed by the number of stops u dial in. But the subject is now correctly exposed if u have chosen the right amount to dial in while the background will be blown out. So u are in effect sacrificing the background bec u want the subject to fill only a small portion of the frame and it's the subject that is more important to u. Of course u can move so that the subject fills like 1/3 of the frame at least.... then u won't need to compensate but the flash will take care of the exposure of the subject.......

 

[deslim27]

i'm not sure on how to use the compensation method.. coz by theory.. if i inc exposure compensation.. from what i understand.. this increases the overall exposure of the whole picture... so there wouldn't be much difference between the object and the bright background as without exposure compensation??

think there's some misconception with my explanation.. mind correcting it??

Pls ignore my message.. misinterpret your question.. TME is probably right about it.

 

[TME]

Yeah the subject must at least occupy 1/3 of the 14-segments I Think in order for the TTL to work well...... which is why I mentioned to iceberg that if u must keep the subject small like group photo or individual with lots of background (bec u want the scenery), then compensate.... the TTL sensor will misunderstand what u are aiming at in the above scenario.........

 

[iceberg]

i see.... mm.... :thumbsup: :thumbsup:

shall try it out this weekend
thanks thanks.

 

[TME]

i see.... mm.... :thumbsup: :thumbsup:

shall try it out this weekend
thanks thanks.

I also tried actually...... looked at the metering display..... I was metering a cactus plant in my balcony at 5pm with the evening sun coming in at an angle. I had to stop down to f/16 to get 1/125 or 1/200 cos my flash dun have HSS.......

What I did was to fill the frame up with the cactus plant with the background bright from the sun. I was on centre-weighted metering. Then I spot metered the plant and looked at the display. The plant was -1EV while the shelves were 0EV and the background was between +2.0EV to >+3EV... so I guess the flash would fill in the plant for me.... hopefully my flash powerful enough to fill in one stop.

I also tried to shoot at f/5.6, 1/200 even though the flash will not sync....... I wonder how it will turn out...... just an experiment...... still got film left over...... wonder when then can finish using.....

 

[yeocolin]

TME, you still have film left over? Just out of curiosity, how long do you take to finish 1 roll of film? Are you using slides or negatives?

If you are using slides, can you tell any degradation in colour saturation if you've left your film half used for more than 2 weeks?

 

[TME]

TME, you still have film left over? Just out of curiosity, how long do you take to finish 1 roll of film? Are you using slides or negatives?

If you are using slides, can you tell any degradation in colour saturation if you've left your film half used for more than 2 weeks?

Yeah, if my father is using the camera for P&S purposes, there will be film left over...... For me, I always finish that roll in the camera....... and I usually shoot more than 1 roll most of the time at one go........

Frankly, I have used film left in the camera for a few months but the prints don't look different to my eyes lar.......

BTW, I use negatives exclusively..... haven't tried slide before but may do so one day........ one day that is.........

 

[yeocolin]

oh, no wonder. Cos slides, especially professional slides such as velvia, provia, are 'matured' to produce optimum colour saturation, hence they are kept in a fridge until they are sold, and usually stored that way until they are used. By leaving it out in the tropical heat of Singapore for too long, the vibrancy of the professional slide film would probably be no different from the amateur slide films, such as sensia.

 

[TME]

oh, no wonder. Cos slides, especially professional slides such as velvia, provia, are 'matured' to produce optimum colour saturation, hence they are kept in a fridge until they are sold, and usually stored that way until they are used. By leaving it out in the tropical heat of Singapore for too long, the vibrancy of the professional slide film would probably be no different from the amateur slide films, such as sensia.

I probably use ordinary slides first when I shoot...... no need Provia or some as exotic.. no point paying for it when I may screw up the entire roll...........