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03-05-2019, 05:06 AM   #1
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Lensbaby Lenses with Flash

Hi peeps,

As I get my head around how to use flash both on and off cameras with regular lenses, I'm stumbling into the frays as to how best approach the process of managing flash with my two lensbaby lenses (Sol45 and Velvet 56). I don't think what I am going through is strictly related to lensbaby lenses, perhaps these hurdles are also apparent with other K mount non A setting lenses?
When you buy a lensbaby lens it wants you to use it in Av mode (without flash that is, it doesn't mention at all any help for flash use), the manual clearly states this. There is no control of the aperture from the camera body (and with the Sol45 there is no aperture to adjust at all, it's fixed at f3.5), instead you use the barrel to adjust the aperture. "Fine... cool, so what.... other lenses are like that as well."... well... yes and no. I have a couple of K Mount lenses that don't quite work the way a lensbaby lens does. If I use a K mount lens in Av mode, it doesn't matter what aperture I change on the barrel of the lens, it will always take the shot wide open, whereas with the lensbaby range it will actually accept the different apertures chosen on the lens in Av mode. Furthermore, when you stop down the aperture it's like you're getting 'optical preview' all the time (screen gets darker etc), so despite the camera body not knowing the aperture (F--) the shutter speed and EV compensation all works, it gets enough feedback from lens aperture reading to calculate and give a proper exposure in Av Mode. You can choose to also experience the lens in Manual mode, if choosing Tv Shift as your green button option then indeed it works and shutter speed will be shifted for correct exposure (or whatever exposure you have set in conjunction with the EV comp). So yeah, in Av or Manual mode you get a pretty decent shooting experience (better than K Mount imo).

So what happens when you attach a flash, either a Pentax branded one or Cactus v6ii trigger (whilst a lensbaby is attached)? Well... in Av mode the shutter speed just locks up at 1/200. Auto ISO never displays the ISO value anymore and just says 'AUTO' . In fact AUTO iso actually doesn't seem to do anything, all the shots report at being 100 ISO regardless of aperture chosen
Ev compensation +/- doesn't do a thing now (whereas before it would), the only thing that seems to change the ambient exposure is the aperture chosen on the barrel and changes in ISO setting.

Being stuck at 1/200 is not the problem, what I find difficult is other than chimping there doesn't really seem to be a way to gauge at all proper exposure. I can't even do this with a V6ii sitting in the hotshoe and not triggering a flash. It's all 'guess work'

If I try Manual mode and use the Green Button to Tv Shift that might help, but when the flash is on the Green Button does nothing and you can't Tv Shift :'(

What should my approach be? Before turning the flash on, go into Manual Mode, set the aperture to what I want to use, set ISO 100, hit the green button (Tv Shift), not the shutter speed given and then keep repeating that process of adjusting ISO and green buttoning until I get close to 1/200? Then turn the flash on and try and manage it? :/

Of course none of this takes into account what the flash might be doing in P-TTL mode, no idea currently if it's behaving or even adjusting in power depending on my +/- EV comp (will have to test this).

Honestly it's a mess... but I am keen to get my head around it because I think some flash shots with the lensbaby lenses could be really really good!

Does anyone understand what I'm talking about with any of this? Anyone offer some words of wisdom other than 'give up' ahhaha


TIA!

Bruce

03-05-2019, 07:16 AM - 2 Likes   #2
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Manual modes on both camera and flash trigger is probably the way to go, as indeed it is for M and K type Pentax lenses. I don't know if the lensbaby lens behaves any differently, but stop down metering would normally be needed for the ambient exposure values. These days with histograms and instant LCD image reviews, i think most of us would take a quick stab at a manual flash power guestimate, then assess and adjust as needed.

I always establish the ambient EV first and then add the flash contribution on top ..... Ot course if you're indoors and not recording any ambient light then just jump straight to assessing the flash exposure.

I think we all gain a sort of sixth sense for the flash power levels ...eg indoors with my softbox very close to the subject, at ISO 100, F8, 1/180th I start out at 1/8th power and that is usually very close
03-05-2019, 07:23 AM   #3
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QuoteOriginally posted by BruceBanner Quote
What should my approach be? Before turning the flash on, go into Manual Mode, set the aperture to what I want to use, set ISO 100, hit the green button (Tv Shift), not the shutter speed given and then keep repeating that process of adjusting ISO and green buttoning until I get close to 1/200?

With the flash off establish your ambient exposure using green button or meter in Manual exposure mode. You dont need to get the shutter speed up to 1/200, just as long as it is at or below the sync speed (1/200)

Then use the flash in Manual flash mode adjusting the settings either on the flash itself or using the Cactus trigger. Because the camera has no idea of the lens ID or of it's aperture, P-TTL won't work. So on the Cactus use manual power output (you still need to set the flash to P-TTL because that is how the Cactus system works.
03-05-2019, 08:39 AM - 1 Like   #4
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I think he's probably going to use the RF60x Peter ....

03-05-2019, 09:48 AM   #5
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Start with the absolute basics, guide number = aperture x distance. Once you have mastered that you can move on to mixing ambient and flash, multiple off-camera flashes etc. That simple equation works for any manual flash and any lens aperture and will save some guess work in getting to a good starting point. You might find Strobist useful if you haven't seen it before - Strobist: Lighting 101: Introduction
03-05-2019, 01:08 PM   #6
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QuoteOriginally posted by mcgregni Quote
Manual modes on both camera and flash trigger is probably the way to go, as indeed it is for M and K type Pentax lenses. I don't know if the lensbaby lens behaves any differently, but stop down metering would normally be needed for the ambient exposure values. These days with histograms and instant LCD image reviews, i think most of us would take a quick stab at a manual flash power guestimate, then assess and adjust as needed.

I always establish the ambient EV first and then add the flash contribution on top ..... Ot course if you're indoors and not recording any ambient light then just jump straight to assessing the flash exposure.

I think we all gain a sort of sixth sense for the flash power levels ...eg indoors with my softbox very close to the subject, at ISO 100, F8, 1/180th I start out at 1/8th power and that is usually very close
I haven't quite got there yet, at least not with consistent lights and modifiers. If I mastered the 360II on camera with a certain modifier all the time, in manual mode, I might, but I usually run and gun with it in P-TTL so I feel I gain little knowledge of what equivalent power it's using. When I do my studio work (product photography) I don't have a consistent approach yet, once you place the flash in different soft boxes I'm always adjusting power differently. Ah well... I'll learn eventually

QuoteOriginally posted by mcgregni Quote
I think he's probably going to use the RF60x Peter ....
Yeah, but also some 360II with the roundflash box could derive some striking images I reckon as well.

QuoteOriginally posted by pschlute Quote
With the flash off establish your ambient exposure using green button or meter in Manual exposure mode. You dont need to get the shutter speed up to 1/200, just as long as it is at or below the sync speed (1/200)

Then use the flash in Manual flash mode adjusting the settings either on the flash itself or using the Cactus trigger. Because the camera has no idea of the lens ID or of it's aperture, P-TTL won't work. So on the Cactus use manual power output (you still need to set the flash to P-TTL because that is how the Cactus system works.
Yeah, so it's as I thought, I have to get some kind of ambient exposure concept first before toggling the flash on. And yeah of course P-TTL won't work properly if the camera body is missing information. Thing is tho... how does the lensbaby lens work then in Av mode if the camera body never knows the aperture yet can always expose correctly So does P-TTL actually kinda work in this weird situation?? Of course in Av mode the aperture is fixed, shutter speed fixed and Auto ISO broken (when flash is turned on and attached) lol, so it's not a good mode to be in. I just feel a little lost without being able to use my EV +/- (not like how I can when a flash isn't connected), I get no feedback on any exposure situation from the camera, only chimping can I get a sense of where I'm at. I tend to rely on the +/- EV comp to kill my ambient light by -1.0 etc but now I can't use this feature with a lensbaby...
03-05-2019, 01:23 PM   #7
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Without the aperture coupling through the mount the camera cannot know the aperture, so P-TTL won't work regardless of what camera mode is used.

Using Av mode with a fully manual lens does not mean that the camera knows, or is controlling, the aperture..... It just means that the Shutter speed (and potentially ISO) is free to float and adjust in response to the light entering the camera. This varies depending on both the actual brightness in the scene and the aperture setting on the lens (assuming fully manual aperture). So the meter is working to control the shutter speed and ISO (which is what normally happens in Av mode with Auto-ISO), but it just cannot control the aperture.

In manual mode the difference is that the shutter speed is fixed by the dial, and only changes with dial adjustments or green button stop down (TV Shifts).
03-05-2019, 01:31 PM   #8
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All manual settings and it can work quite well. I usually play around with the flash power and start off pretty close to what mcgregni suggested.

03-05-2019, 03:32 PM - 2 Likes   #9
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QuoteOriginally posted by BruceBanner Quote
I usually run and gun with it in P-TTL so I feel I gain little knowledge of what equivalent power it's using.

I think you should stop trying to relate P-TTL automatic outputs to fixed manual flash power levels .... there's really no point, as the two have no theoretical or practical relationship. When using P-TTL with a Pentax flash you have the Range display to guide you (when on camera and straight ahead). All that matters is that the subject distance is within this range. Anything further and you can assume that correct exposure would exceed the flashes maximum output capabilities. But with the metering aspects we can never know for sure whether the flash will actually output its maximum, because the metering may be reducing it somewhat. So its all conjecture, and no help in practice.
03-07-2019, 03:55 AM - 2 Likes   #10
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Well I had a couple of tries and I think I'm getting there, though honestly I find I just have to jump into manual mode and just chimp a lot and adjust what I think I see needs adjusting, it's definitely not easy like running & gunning P-TTL with AF lenses!

Sol Splash



#lovelydeadcrap


Both taken with the Sol45.
03-07-2019, 04:15 AM   #11
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Nice effects, very atmospheric, and worth the extra effort with Manual mode flash! Now imagine what this would have been like back in the days of film ....I know for sure I would never have developed many flash skills then, as experimenting and learning would have cost too much in film developing . I know that only through digital could I come to use flash.
03-07-2019, 12:05 PM   #12
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QuoteOriginally posted by mcgregni Quote
Nice effects, very atmospheric, and worth the extra effort with Manual mode flash! Now imagine what this would have been like back in the days of film ....I know for sure I would never have developed many flash skills then, as experimenting and learning would have cost too much in film developing . I know that only through digital could I come to use flash.
Yeah that's a really good point, though I shudder to think what my shutter count might be!
03-07-2019, 12:20 PM - 1 Like   #13
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I know my shutter counts with film SLRs were low! If I got 20 well exposed shots out ot each roll of 36, that was pretty good ....I hate to think what that figure would have been if id added manual flash with manual aperture lenses into the mix as well!! .... But then again, plenty of pro photographers back then must have been able to do it!
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