What Lenses to use for ROM and Wedding??


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Hi TME,

Hmmm .... somehow this discussion is interesting to me.

Anyway, I know that in normal case when you not using a flash and you dial in exposure compensation, the shutter speed or aperture changes like what you have described - to either allow more or less light in. However, if you are using flash, say in A mode, then you will notice that the shutter speed setting doesn't change for the same focal length lens used (maybe I will try it out tonight, and why don't you try it out too - I stand to be corrected :D ) irregardless of whatever compensation you used. In this case, the only way you can increase the ambient exposure (for the same aperture value) is to switch to manual mode and select a slower shutter speed (the way i normally do) or use the slow sync function (but this might get you too low a shutter speed).

You may ask why is this so? This is because for minolta cameras, when you use flash and in A mode for eg, the camera will select the shutter speed that will be roughly 1/focal length of the length used with the max limit being the sync speed of your camera and the min limit being about 1/50 or 1/60s (not too sure about this) i think. That is to say, if you using a 28-70mm lens and say you zoom up to 70mm ..... your shutter speed would be set at 1/60s. And if you using a 200mm lens, then your shutter speed would be around 1/200s. Note again that this applies only when you use flash. So what effect do you have when you set exposure compensation? Well, the flash will provide the main lighting and therefore watever compensation you set, the flash will either increase or decrease its output. Another way of looking at it is that the camera will try to maintain a shutter speed for you that is below the sync speed and something which you can handhold. For example, if initially your shutter speed is 1/60s and say you dial in +2 stops exposure compensation, then if you say that this will change the shutter speed setting, the camera would have to set it at 1/15s and this to some (or many) pple is too slow for hand holding. So the camera actually doesn't change the shutter speed and for this example will still remain at 1/60s but the flash will provide +2 stops more light. That said, I have to disagree with your stand that setting exposure compensation doesn't affect the flash lighting up your subject.

Hope you get what I was trying to say. :)

Jerry
 

Hi, Jerry,

Yupe, I find this discussion very interesting... :D

I am testing the camera in the way we have discussed as I'm typing this! And u know what? I think u are right... with regard to your observations. Zerstorer can u comment?

Equipment:
Camera - Dynax 7,
Lens: Tamron 24-135mm SP f/3.5-5.6
Flash: 3500xi program flash

Settings:
Camera - centre-focus spot, 14-segment honeycomb (evaluative) metering, A mode at f/5.6
Flash - TTL, auto mode.

Environment/Object:
Steam iron under fluorescent lighting in a HDB bedroom. I'm using the largest fluorescent tube there is on the market - I think the 40W one...... anyway it's 3 feet long.. just to give u an idea of the lighting condition under which I carry out the testing.

Part 1 - Exposure compensation, no flash compensation
1) With flash mounted on hotshoe.


At 135mm focal length:
f-stop shutter ex. com flash com
f/5.6, 1/125 sec, +0.0EV 0.0
f/5.6, 1/125 sec, +1.0EV 0.0
f/5.6, 1/125 sec, +2.0EV 0.0
The shutter speed does not change!

At 70mm focal length:
f/5.6, 1/90 sec, +0.0EV 0.0
f/5.6, 1/90 sec, +1.0EV 0.0
f/5.6, 1/90 sec, +2.0EV 0.0

At 50mm focal length:
f/5.6, 1/60 sec, +0.0EV 0.0
f/5.6, 1/60 sec, +1.0EV 0.0
f/5.6, 1/60 sec, +2.0EV 0.0

At 24mm focal length:
f/5.6, 1/60 sec, +0.0EV 0.0
f/5.6, 1/60 sec, +1.0EV 0.0
f/5.6, 1/60 sec, +2.0EV 0.0

Shutter speed seems to change with focal length rather than with exposure compensation! Why?

2) Without flash at all

At 135mm focal length:
f-stop shutter ex. com flash com
f/5.6, 1/10 sec, +0.0EV 0.0
f/5.6, 1/6 sec, +1.0EV 0.0
f/5.6, 1/3 sec, +2.0EV 0.0
The shutter speed change with changing compensation!

At 70mm focal length:
f/5.6, 1/10 sec, +0.0EV 0.0
f/5.6, 1/6 sec, +1.0EV 0.0
f/5.6, 1/3 sec, +2.0EV 0.0

At 50mm focal length:
f/5.6, 1/8 sec, +0.0EV 0.0
f/5.6, 1/4 sec, +1.0EV 0.0
f/5.6, 1/2 sec, +2.0EV 0.0

At 24mm focal length:
f/5.6, 1/8 sec +0.0EV 0.0
f/5.6, 1/4 sec, +1.0EV 0.0
f/5.6, 1/2 sec, +2.0EV 0.0



Part 2 - Exposure compensation + flash compensation
1) With flash mounted on hotshoe.

In all cases, the shutter speed did not change with the change in flash compensation, either in the + or - direction and whether there was exposure compensation dialled in or not.

2) Without flash at all
Not relevant since there is no flash.

So it proves that Jerry is right in his observation that
(1) The shutter speed does not change regardless of the exposure compensation dialled in.
(2) The shutter speeds change according to the focal length. However, the data also shows that for the wider end, the shutter speed stays constant at 1/60 sec. I did more testing and found that the shutter speed (regarless of compensation) remained at 1/60 from 24mm to 65mm, and at 1/90 from 65mm to 90mm, and then at 1/125 from 95mm to 135mm.

Now for the comments/questions/deductions..... :D

1) If the aperture and shutter speeds do not change when u dial in exposure compensation with the flash on, then how does the camera let in more light or reduce incoming light? in this case, it would seem then that it is the flash duration that does the compensating..... in which case then if u dial in +1EV, the flash will now fire longer (flash output may also be modulated accordingly). This means more light is reflected off the subject and the film plane gets hit by more light, effectively increasing the amount of light entering the film plane. And the converse if true as well if u dial in -1EV compensation.

2) Following from the comment in (1). But, while this (1) does wonders for the subject's exposure, what about the ambient lighting? The flash's power cannot increase or decrease the amount of ambient light coming through the shutter and onto the film plane. In order to increase the level of ambient lighting captured on film, we must necessarily do one of two things - reduce shutter speed, or increase aperture size (i.e. decrease f-stop number). Now since this does not occur automatically, then it would appear that it has to be done manually. That is if u want to set the DOF, u have to first focus and then switch to manual mode to drop the shutter speed. If u set shutter speed, then u have to open up the aperture instead.

For example, say u meter at f/5.6 (A mode) and get 1/60 sec shutter seed. Compensating for +1EV will brighten the subject but not the background. It stands to reason that the background is not affected since the aperture size and shutter speed remains the same regardless of the level of compensation and therefore the amount of light from the background hitting the film plane remains the same. It therefore remains for us to manually alter either the aperture size to increase the level of ambient light that reaches the film plane for that shutter speed.

3) Following from the reasoning and conclusions in (2), it must mean now that if the original settings with +1EV compensation was f/5.6 and 1/60sec, the subject will necessarily be overexposed by one stop if the compensation was executed by the change in the length of the flash output! This would immediately mean that your subject will now have that "caught-in-that-headlamp" look because the flash has been forced to fire longer. Yet we know that the flash pulse is cut by the TTL sensor inside the film plane. That is the flash pulse is cut by the camera's TTL sensors once it senses that the subject is sufficiently lit for correct exposure. If this were so, then the subject will not be overexposed. But then where does the +1EV then go to if the flash cannot fire longer than it takes to light the subject properly?! Notice the illogicality here... :D

NOTE: But the Dynax 7 manual (pg. 80, pts. 1 and 2) says that when exposure compensation is dialled in with the flash on, the exposure will be compensated by adjustments to the shutter speed, aperture AND flash burst! What has been observed for the situation without the flash matches point 1.
But in real world experience, it seems that in A mode, or S mode, neither the shutter speed nor the aperture changes respectively! And whether or not the flash burst changes, we do not know since there is no indication on the data panel of the camera. (My 3500xi flash does not have a data panel). And therefore there is some discrepancy between pt 2 and my experience. So the question then again is how does the compensation take place?

4) And to make matters less confusing, the shutter speeds in A mode do not change at all regardless of the level of flash compensation. This corroborates what is written in the Dynax 7 manual (P.g. 80 pt. 3). It is also specifically mentioned in the manual pg. 103 that flash compensation does not affect ambient light exposure. This leads to the next point

5) If the manual is correct that flash compensation does not alter ambient light exposure, it stands to reason that the exposrue compensation cannot be taken care of by the duration and power of the flash burst! Therefore the compensation must still come from the change in the shutter speeds in A mode.
This explains pg. 80 of the manual pt 2. The reason for the change in flash burst, I suspect is that with more light coming in now, it also means that more of the light reflected by the subject from the ambient light now enters the camera and hits the film plane. And so the flash burst duration must be a little shorter to compensate for this such that the subject will not be overexposed. In other words, the time taken for the subject to be lit correctly is now shorter as there is more light being captured and therefore the flash cuts off faster.

6) As to why the shutter speed did not change, I think it might have to do with me selecting a moderately large aperture... although if this was the reason, then it must mean 2 things:
a) That the room is sufficiently bright such that the background lighting and the brightness of the subject are almost the same. Therefore the camera did not change the shutter speed since no compensation is required. Doesn't sound right as well huh?
b) It also means that the shot with compensation and without compensation will look the same when printed out. Probably will not possible to notice with prints but maybe with slides it's possible. The reason is of course, there is no change in shutter speed nor aperture so the amount of light coming in should be the same. The flash modulates its duration and power according to the amount of light detected by the TTL sensor, and so it will play no part in increasing or decreasing the exposure of either background or the subject as it also does not change its duration and power as the level of light entering the camera off the subject remains the same with or without exposure compensation (only in this case). This sounds better and more logical.

Okie... it's time to sleep... I'll try the same scene tomorrow night with different apertures this time and see whether the shutter speed changes or not in A mode. In the meantime, happy reading... :D.. tata!
 

Woah!! I didn't know that posting on the forum also got character limit. Thought only PM got such limit. BTW, the character limit for CS is 10,000. I hit 10,0052 and had to cut down a little to hit exactly 10,000 characters...... phew!! Must be a record length in CS......... sorry but I hope all who have been part of the marvellous discussion take the time to read what I have thought through.......... thanks!
 

hey...interesting discussion here...

let me join in....
so from what i gather, there's no point in changing the compensation on the camera as the setting will not change and it will not affect the flash too. unless you compensate on the flash, but the TTL will cut the flash off when it sense that the exposure is correct for the subject.

so the only thing we can do is to set the camera to manual in order to increase the ambient light?

so...
f5.6, 1/30 have more ambient light with the same exposure on the subject with f5.6, 1/60?
 

Wow! That is really something .... hahaha.

I played around a bit with my camera last night too (though nothing as extensive as your analysis) to confirm my logic. Well, results is as what you said.

Things are rather straight forward without flash so I won't go into that. So I will try my best to point out wat I think of your analysis.

- Agree with you on point 1 and 2 of your analysis.

- From pt 3 onwards, I kinda disagree in some aspects. You are right that the flash sensor cuts the flash pulse when it thinks that enough exposure is obtained. Nevertheless, your camera metering sensor is with reference with watever exposure compensation you set or with the iso setting of the film. So if you +1ev (or if you set a 400 film as iso 200 for eg- the effect is the same), the camera basically increases the exposure required by one stop - it doesn't really know if this gives the exact exposure or not. Basically, the photographer is the one who must decide if you want to have an extra stop of light or not in order to obtain the correct exposure - not the camera. The camera, its just a tool and since you "tell" it to give an extra stop of light, it will. As automatic as it is nowadays with the current advanced metering system, it is still not entirely perfect, and there are many situations whereby the photographer has to override the camera's recommended exposure settings (with or without flash).

- The manual is right that flash compensation does not affect ambient. Ambient here refers to the background whereby the range of the flash does not cover. And since setting flash comp only adjusts the flash ouput ..... so its right to say it doesn't affect the ambient exposure.

- Exposure compensation does affect the flash output. In fact, setting exp comp OR flash comp gives the same effect to the subject that is lighted up by the flash. Setting both TOGETHER results in a cumulative compensation. ie. exp comp + flash comp = total comp for flash output.

- Lastly, shots with and without compensation will not be the same since exp comp affects the flash output as well. If it looks the same in prints then it may have been compensated by the lab (the latitude of print films nowadays is amazing). Shoot it with slides and it becomes obvious for even 0.5 stop.
 

Can't comment on pts 1 and 2 since I don't own a Dynax 7, it appears that Jerry may be right.

I have a query here, for those who have a flash with LCD display, is the EV compensation added by the body reflected in the flash output display on the LCD?

For Pt3. TTL flash tries to give you the correct exposure only at default settings. If you override the flash compensation by 1EV, you are basically telling it to add 1EV to what it originally thought was correct. Thus there is no logical conflict here. Note that a correct exposure is always with reference to a middle grey subject. If the subject has a much greater or lesser reflectivity, the exposure will then be incorrect and compensation must be applied according to your experience. This applies to normal metering as well.
 

Zerstorer said:
Can't comment on pts 1 and 2 since I don't own a Dynax 7, it appears that Jerry may be right.

I have a query here, for those who have a flash with LCD display, is the EV compensation added by the body reflected in the flash output display on the LCD?

For Pt3. TTL flash tries to give you the correct exposure only at default settings. If you override the flash compensation by 1EV, you are basically telling it to add 1EV to what it originally thought was correct. Thus there is no logical conflict here. Note that a correct exposure is always with reference to a middle grey subject. If the subject has a much greater or lesser reflectivity, the exposure will then be incorrect and compensation must be applied according to your experience. This applies to normal metering as well.

I don't have a dynax 7 too (uses the dynax 9 and the x700), but if I remember correctly, the ev compensation is not reflected in the flash LCD display of my 5400.

Agree with you totally.
 

Ok, just thought of a reason that may account for the results of 1).

Minolta cameras always attempt to maintain a minimum of 1/focal flash sync speed when flash is used. Nikon cameras always adopt 1/60 regardless of focal length.

However, the above condition applies when the ambient light simply doesn't allow for a proper exposure when the shutter speed is higher.

What if you were to try the EV exposure setting on the camera when light is ample(fill flash situations). (eg, camera meters 1/125 on a 50mm without flash but you turn on flash and set +1EV on camera.) It should then set the shutter speed to 1/60 as expected.

I'm thinking that EV compensation==flash compensation only in situations where the flash is the main source of light.

This is because the camera imposes the shutter floor of 1/focal length in A/P modes. Thus since there is no way of increasing ambient exposure further without lowering the shutter speed, the flash output is increased.

However, when in situations of adequate light where the camera shutter speed is above the minimum allowed, the EV compensation feature should still work as normal(i.e independent of flash compensation).
 

Sudden revelation. Did you test the flash with Slow-sync enabled?

The default flash sync speed may be the cause of the results above.

Slow-sync mode should remove the flash-sync speed limitation and allow the camera EV settings to work as normal.
 

Zerstorer said:
However, the above condition applies when the ambient light simply doesn't allow for a proper exposure when the shutter speed is higher.

What if you were to try the EV exposure setting on the camera when light is ample(fill flash situations). (eg, camera meters 1/125 on a 50mm without flash but you turn on flash and set +1EV on camera.) It should then set the shutter speed to 1/60 as expected.

I'm thinking that EV compensation==flash compensation only in situations where the flash is the main source of light.

This is because the camera imposes the shutter floor of 1/focal length in A/P modes. Thus since there is no way of increasing ambient exposure further without lowering the shutter speed, the flash output is increased.

However, when in situations of adequate light where the camera shutter speed is above the minimum allowed, the EV compensation feature should still work as normal(i.e independent of flash compensation).

Interesting observation. Makes sense since I remember that in fill flash conditions, the shutter speed does not necessary stay at 1/focal length - it might be faster than that. Setting exposure compensation might change the shutter speed accordingly (in A mode). Got to test this out to confirm though.

One thing to point our though, when you meter WITHOUT the flash on and WITH the flash on, the exposure settings may be very different! The real exposure is when you turn OFF the flash. When you ON the flash, the camera seems to take into account the flash output and therefore, the metering shown in the camera is not necessary the right one.
 

Maybe I should also add that in outdoor/fill flash situation, what I normally do is to set at manual, OFF the flash and take a metering of the environment. Then I on the flash and stick to the metering i took earlier (ie ignore the new exposure setting with the flash on) and fire off. This should give a 1:1 fill ratio. To reduce the fil ratio, I just set -ve flash comp. Normally, -0.5 to -1.0 gives pleasant fill-in.
 

Zerstorer said:
Sudden revelation. Did you test the flash with Slow-sync enabled?

The default flash sync speed may be the cause of the results above.

Slow-sync mode should remove the flash-sync speed limitation and allow the camera EV settings to work as normal.

By depressing the slow-sync button, exp comp should change the shutter speed in A mode - like you said.
 

Zerstorer said:
Sudden revelation. Did you test the flash with Slow-sync enabled?

The default flash sync speed may be the cause of the results above.

Slow-sync mode should remove the flash-sync speed limitation and allow the camera EV settings to work as normal.


Wahh!!! So many comments...... anyway no I did not switch to slow sync. It was normal so to speak.
 

In any case Jerry, my bone of contention is that in the case where the shutter speed and aperture size do not change as evidenced in the data I posted, then how does the compensation take place such that an increased ambient light level is captured? Which to my understanding is one of the reasons for overexposing under low light. Whether the flash fires longer or not does not matter since it cannot change the intensity of the ambient light. And the only factors that govern the level of ambient light entering the camera are the aperture size, shutter speed and film speed (which is kept constant in any case) while the former two do not change regardless of how many stops dialled in.


For that matter, whether the flash fires longer or not when u +1EV is open to debate especially if the shutter speed actually drops.

Let's consider if the shutter speed remains constant after +1EV. For a TTL flash, it will cut off once the TTL sensors sense that the subject is lit properly. Whe u meter the scene, the camera will detect that the subject is underlit and instructs the flash to fire for certain duration in order to attain a certain level of reflection of light off the subject which the TTL sensor will receive and which the camera deems as sufficient to light the subject properly. Therefore, if this holds true when u +1EV, then the subject will always remain properly exposed (within limits) since once sufficient light from the subject is detected the flash is cut off. And it also means that the flash will do its TTL thing whether or not u dial in any exposure compensation. Thus the flash is independent of the exposure compensation. And we can then say that dialling in exposure compensation has no effect whatsoever on the scene.

If the shutter speed does actually become slower as I was expecting, then this makes the flash fire for an even shorter time now cos more light can enter the camera now with a slower shutter speed. Thus only in this scenario can one say that the exposure compensation affects the flash output/duration directly as u have mentioned.

However as the first scenario is the one we observe, then flash system is effectively decoupled from the exposure compensation. For the flash system to be dependent or affected by the exposure compensation, it would mean that the flash must fire longer than what the TTL sensors tell the flash (based on the level of reflected light). This must necessarily mean that the subject gets overexposed! And it would also mean that under low light, we override the TTL sensors with our exposure compensation!

In addition, I am not sure if what Zerstorer said was accurate about the Minolta system always trying to maintain shutter speed at about 1/focal length under low light. Because if this were so, then it would mean that the Minolta system inherently tries to maximise the level of ambient light under low light. And this therefore explains the "constant" shutter speed since the camera does not allow u to go below 1/focal length unless it has no choice. Therefore at these lighting levels, exposure compensation is not functional?

Haiz... getting rather confusing...... time to sleep! :D I eagerly await your replies! :devil:
 

I was studying the Dynax 7 manual again, and the manual specifically states that in A mode, only the shutter speed changes and in S mode, only the aperture changes. And under the custom function, one can set the flash burst to be "varied" or "fixed" when used in conjunction with the exposure compensation. It mentioned that in the "varied" mode, the flash will compensate for subject inside or outside the flash range. I think what it means is that the flash will cut off once the subject is correctly lit. On the other hand, the "fixed" mode means the flash output is not changed and so the exposure within the flash range is more or less constant. This would mean that the subject will probably be overexposed.

What do u all think about the data I posted in the light of what the manual states? :D Sure if confusing isn't it?!
 

TME said:
In any case Jerry, my bone of contention is that in the case where the shutter speed and aperture size do not change as evidenced in the data I posted,
I believe that Jerry is right in the EV compensation doesn't work as normal in A/P/S modes using flash. This is because of the camera's logic in limiting the flash sync speed to prevent blurred images(applies to normal users). Only when you specifically select slow-sync(typically only more advanced users will play with this) mode will the EV compensation work as normal.


then how does the compensation take place such that an increased ambient light level is captured? Which to my understanding is one of the reasons for overexposing under low light. Whether the flash fires longer or not does not matter since it cannot change the intensity of the ambient light. And the only factors that govern the level of ambient light entering the camera are the aperture size, shutter speed and film speed (which is kept constant in any case) while the former two do not change regardless of how many stops dialled in.


I would think that EV compensation works similarly to Flash compensation in this case.


Let's consider if the shutter speed remains constant after +1EV. For a TTL flash, it will cut off once the TTL sensors sense that the subject is lit properly. Whe u meter the scene, the camera will detect that the subject is underlit and instructs the flash to fire for certain duration in order to attain a certain level of reflection of light off the subject which the TTL sensor will receive and which the camera deems as sufficient to light the subject properly. Therefore, if this holds true when u +1EV, then the subject will always remain properly exposed (within limits) since once sufficient light from the subject is detected the flash is cut off. And it also means that the flash will do its TTL thing whether or not u dial in any exposure compensation. Thus the flash is independent of the exposure compensation. And we can then say that dialling in exposure compensation has no effect whatsoever on the scene.


In a normal case in manual mode, this would be true. But since the shutter speed is locked in A mode with flash. There can only be 2 possible outcomes of +1 EV compensation.

1)The EV compensation is ignored and the exposure is as normal
2)The Flash TTL sensors are instructed to allow for 1EV more exposure than usual.

Someone will just have to confirm which actually takes place by shooting some slides.


In addition, I am not sure if what Zerstorer said was accurate about the Minolta system always trying to maintain shutter speed at about 1/focal length under low light. Because if this were so, then it would mean that the Minolta system inherently tries to maximise the level of ambient light under low light. And this therefore explains the "constant" shutter speed since the camera does not allow u to go below 1/focal length unless it has no choice. Therefore at these lighting levels, exposure compensation is not functional?


What it should mean in this case is that the Minolta system tries to maximize the ambient light while factoring in the effects of focal length. It will not allow you to go under 1/focal length at all, unless u delibrately override it.
 

But what about the manual? It specifically states that for A mode, only the shutter speed will be altered for exposure compensation. The flash compensation only alters the flash power/duration. And in fact, when u use flash together with A mode, and exposure compensation, both the shutter speed and the flash varies. And there is a custom function for u to prevent the flash from varying..... that is u force the flash to fire a fixed burst..... in effect overriding the TTL sensors of the flash.......

How about that for confusion?!:D

In summary, I think it boils down just to this:

One conclusion we can draw from this is that Minolta camera system does not allow the shutter speed to drop below 1/focal length unless u override the system or the lighting conditions are extreme.

So that begs the question, if in A mode and the shutter speed is at the limit (i..e lowering the shutter speed will make it < 1/focal length) and u dial in +1EV exposure compensation,

1) Does the camera actually compensate?
2) How is the compensation done? Via flash?

Maybe should ask Andy......he'working for Minolta! Maybe he has some answers........... kekeke......
 

Zerstorer said:
But since the shutter speed is locked in A mode with flash. There can only be 2 possible outcomes of +1 EV compensation.

1)The EV compensation is ignored and the exposure is as normal
2)The Flash TTL sensors are instructed to allow for 1EV more exposure than usual.

Someone will just have to confirm which actually takes place by shooting some slides.

Why not shoot a roll of slides and confirm the results for yourself? Then you will have no doubts about the outcome. Can just spend 10 frames testing flash exposure and use the rest to go around shooting some scenery or watever...:)
 

Zerstorer said:

then how does the compensation take place such that an increased ambient light level is captured? Which to my understanding is one of the reasons for overexposing under low light. Whether the flash fires longer or not does not matter since it cannot change the intensity of the ambient light. And the only factors that govern the level of ambient light entering the camera are the aperture size, shutter speed and film speed (which is kept constant in any case) while the former two do not change regardless of how many stops dialled in.


I would think that EV compensation works similarly to Flash compensation in this case.


Then how does the ambient lighting increase throught exposure compensation? Flash compensation only affects the subject since the flash will never be powerful enough to light up the background.......
 

TME said:
Then how does the ambient lighting increase throught exposure compensation? Flash compensation only affects the subject since the flash will never be powerful enough to light up the background.......

If it actually behaves that way, the ambient light will not be affected.

EV compensation would be equal to flash compensation in that case as the flash is acting as the main source of illumination and the camera assumes ambient light to be negligible.
 

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