• Cart
  • Checkout
  • My Account

Infrared Conversions, IR Modifications & Photography Tutorials | Life Pixel IR

The world leader in infrared conversions, modifications & DIY IR conversion tutorials. Scratched sensor replacement, UV & Full spectrum conversions.

The world leader in infrared camera conversions

866.610.1710
  • Home
  • → Start Here ←
    • 1 – Introduction
    • 2 – Filter Choices
    • 3 – Focus Calibration
    • 4 – Lens Considerations
    • 5 – Camera Considerations
    • 6 – Start Shopping
  • Galleries
    • Infrared Photography
    • Infrared Time Lapse
    • Infrared Cinematography
    • Infrared Stop Motion
    • Ultraviolet Photography
    • Forensic Photography
  • Education
    • Training Sessions
    • How To Shoot Infrared
    • AR Coated Infrared Filters
    • Lens Hot Spot Database
    • Photoshop Video Tutorials
    • Infrared Issues & Solutions
    • IR Basics in Photoshop
    • Camera Quick Start Guide
    • DIY Conversion Tutorials
    • IR Photography Primer
    • Secondhand Cameras
    • Wall Of Shame
  • Workshops
  • FAQ
  • Blog
    • Tutorials
    • Inspiration
    • Locations
    • Gear
    • News
    • Other
  • Why Choose LifePixel?
    • Submit Your Review
  • Contact
  • Shop

Medium Format Lenses – Part II

Several months ago, I wrote a blog about using medium format lenses on DSLR.  I wanted to continue this series with a little more information.  In my experience, one of the most understood characteristics of using non-standard lenses with different film/sensor size is crop factor.  Before going into this, let’s get a little background on what crop factor is and why it’s relevant to this blog.

When you use a lens that is intended for a different sensor size or film format, the lens can overfill or under-fill the sensor/film. Using a full format (35mm) lens on a DSLR with a crop sensor (APS-C, Micro Four Thirds, etc), the lens will project an image that is larger than the sensor size.  This overfills the sensor.  In other words the smaller sensor is sitting in the center of a larger image on the film plane.  When this happens, the sensor is only seeing a portion of image on the film plane.  This gives the appearance that the image is zoomed, when compared to the same image on a full format sensor.  The image below represents a full frame DSLR image (35mm format).  The inset square represents the crop factor of an APS-C sized sensor.

It’s important to note that there is no magnification or change in focal length.  It is merely a characteristic of the image size and the sensor/film size.  This is called crop factor.  The most common is when using a full format lens on an APS-C sensor camera.  This gives a crop factor of 1.6.  This is simply the ratio of the smaller image size vs the larger one.  Since different sensors have different aspect ratios (height to width) I prefer to use the diagonal distance for crop factor calculation, as it accounts for both height and width.  A full frame sensor is nominally 36mm x 24mm, which is 43.3mm diagonally.  An APS-C sensor is 22.4mm x 15mm or 27.0 mm.  So 43.3mm/27.0mm=1.6X.

The exact same situation occurs when we use a medium format lens on a DSLR.  I’m currently using Pentax 67 lenses on my full spectrum Canon 5D Mark II.  There is a big difference in film/sensor size.  So there is a significant crop factor.  The film size of a 6×7 is about 6 x 7cm, however the actual size is about 56.0 x 72.0mm, depending on camera format.  Using lenses for medium format on a full frame DSLR provides a crop factor of over 2X.  Using these lenses on an APS-C sensor provides a crop factor of over 3.4X.  In terms of  what was discussed earlier, a 6×7 lens on a full frame DSLR over fills the sensor area by more than 2 times.  It over fills an APS-C sensor by 3.4 times.

A 55mm lens is a 55mm lens.  It won’t matter if this lens is used on a full frame camera or a medium format camera.  The focal length does not change.  Only the field of view changes.  But if you take a photo with a medium format camera and then use the same lens on a full frame DSLR, the DSLR photo will appear to be zoomed by 2X.  But remember, it’s just seeing less of the full image. I did an experiment to validate this and took several Canon L lenses (intended for full frame sensors).  These were compared with images shot with my medium format lenses.  I overlaid them in Photoshop to make comparisons.  With these, it’s easy to see that the medium format lenses have the same field of view as the Canon lenses.

It turns out that crop factor is one of the best characteristics of using a medium format lens on a DSLR.  Most lenses are clearest in the center.  It’s toward the edge of the frame that aberrations occur.  Using the medium format lenses on DSLR’s uses sees the image through the best part of lens, the center.

I love shooting IR with the medium format lenses.  They are hefty and manual focus, but are superb for IR.  They fit the way I shoot IR and provide superb results.  I hope this information helps understand how crop factor affects the field of view and that there is no magic happening when you use medium format lenses on a DSLR.  I also hope it encourages you to do some experimentation of your own.  Happy shooting!

 

Filed Under: Tutorials Tagged With: 5d Mark II, Canon, Eric Chesak, IR Infrared, medium format

Bracketed Exposures for IR photography

What are bracketed exposures? If you’re familiar with this term, you know how useful they can be. There are multiple uses for bracketed exposures, but they are especially helpful in IR photography. Shooting bracketed exposures is where the camera is set-up to shoot the same scene, but at different exposures.

Nearly all stock cameras are meant to shoot in color. So when we get into the optics and start removing filters or adding other filters, the camera doesn’t work the same. The one area that really takes a beating is the metering. After a modification, the metering will still be fairly close. But shooting in IR or full spectrum will definitely change the way the camera’s metering system sees the world. I find that my full spectrum modified Canon 5D Mk II with a 740nm filter will usually meter a ½ to 1 stop (usually denoted by EV) brighter than a normal scene. Most of my other modified cameras were the same.

The shows a series of 3 bracketed exposures at -1, 0 +1 EV

When I shoot IR photos, I shoot bracketed exposures as a rule. I’ve had too many IR photos where I thought the metering was accurate only to find that there are highlights in the scene that are blown out (camera’s histogram is clipped on the RHS). Shooting bracketed exposures nearly always helps me recover these highlights or even allows me to process a different shot that is at the + or – end of the bracket.

How do you begin doing this? Well, most cameras these days will allow the use of bracketed exposures. This is where the camera will shoot 3 or more exposures for each image. Depending on how you set it up, the camera will typically shoot a normal exposure and one under exposed and another that is over exposed. Some cameras will shoot additional over/under frames and also allow you to skew how these different exposures are framed in the overall bracket.  I like to set my camera to shoot the bracketed exposures in high speed mode, so I can get the 3 images in rapid succession with a single shutter button press.

This is the menu option for setting bracketed exposures on a Canon 7D.  This one is set for -1, 0 +1 EV

My cameras (as to many) have several programmable settings where I can set f/stop, ISO, exposure mode, bracketed exposures, etc. So I have 2 custom settings that shoot only bracketed. On my camera, C1 is set up for 1 stop over and under. The camera will record 1 normally metered frame, one frame that is one stop under and one frame that is one stop over. C2 is the same operation except for 2 stops over/under. This makes it quick and easy for me to change the camera to different situations where 1 or 2 stops might be needed.

Many DSLR’s have the ability to set custom settings.  This one is a Canon 5D MkII

So why else would I shoot bracketed exposures? One great feature is HDR. If you’re shooting a scene that has both bright and dark elements or the scene spans more dynamic range than a single shot can record, HDR or some other technique of exposure masking or blending is the way to do this. It’s also very helpful to have multiple exposures when shooting on the shadow side of the Sun, or toward the Sun.  Many times you won’t see the need for HDR until after you return and are processing your images. It’s too late to do an HDR at that point. So by shooting bracketed exposures, you have the ability to do HDR or exposure blending on shots, after the fact.

This is an HDR of the 3 images shown above.

Isn’t shooting bracketed exposures going to wear out my camera? Won’t it take more memory? Yep, for both. Your shutter is now clicking 3 or more times for each scene. All of these shots have to be recorded on the memory card. Of the 7 modern DSLR’s I’ve owned, I’ve only replaced the shutter on one camera (my 30D), and that was at about 3700 clicks, for sure an anomaly.  Most prosumer DSLR’s are good for 100k -150k shutter clicks. I’ve never shot 100k shots on any of my cameras. But I’m not a professional photographer. I venture to guess that most other casual shooters are the same. As for the memory consumption, memory cards are cheap.

Another example of scene that benefited from having more than a single exposure

There is a little good news. If you focus and shoot your IR like I described in my last blog, focusing through live-view, the mirror will stay locked up. So the wear associated with the mirror flipping up and down is removed from this operation.  It also helps to use a tripod when shooting bracketed exposures, especially if you’re going to be using them for HDR. You can still align the images in post-processing. But it’s easier if the images begin with good alignment. I prefer to shoot all my IR with a tripod.

Scenes that are shot toward the Sun typically have a high dynamic range that benefit from having bracketed exposures

If you’re comfortable with shooting regular exposures with your IR photography, by all means proceed. I find that shooting bracketed exposures helps save many images that might have otherwise been unusable. Happy shooting.

Filed Under: Tutorials Tagged With: 5d Mark II, 5DII, Bracketed Exposures, Eric Chesak, full spectrum, HDR, Infrared, IR, Photography

Blog Topics

  • Tutorials
  • Inspiration
  • Locations
  • Gear
  • News
  • Other/Misc

What our customers say:

Life Pixel has been a life-changer for me. Continue reading
Eric GConnecticut
Read more reviews
I am more than satisfied with the service I received Continue reading
Christopher JCanada
Read more reviews
I am more than pleased with the conversion job that you did Continue reading
LOUIS MWaco, Texas
Read more reviews
I am VERY impressed with his knowledge of your products and his patience in explaining it to a novice like me. Continue reading
Lynn FEssex, Maryland
Read more reviews
Things will only get better from here thanks to all of you. Continue reading
Phillip FRedding, California
Read more reviews
The Lifepixel newsletter reminds me of not having expressed my gratitude for the excellent job you made. Continue reading
Michael GGermany
Read more reviews
Your staff went above and beyond the call of duty to make sure everything was handled in an excellent manner. Continue reading
Paige RPearland, Texas
Read more reviews
It has given my old camera a new life, I will enjoy using it again. Continue reading
William PAustralia
Read more reviews
Excellent service and the camera works just great Continue reading
Hans FairhurstAustralia
Read more reviews
I just got my converted camera back from you guys. THANK YOU!!!! Continue reading
Anne CutlerForest Knolls, CA
Read more reviews
infrared_filter_choices_sidebar
ir_conversions_explained_sidebar
----------- Watch More Videos -----------
infrared_quick_start_guide

Ready to start shooting Infrared?

Convert My Camera

Subscribe To Our Newsletter

Receive updates, tips, cool tutorials, free stuff and special discounts.

Learn the Basics

  • Video
  • Start Here
  • Filter Choices
  • Focus Calibration
  • Lens Considerations
  • Camera Considerations
  • Place Your Conversion Order

Resources

  • Galleries
  • Lens Hot Spot Database
  • IR Tutorials
  • FAQ
  • Infrared Filter Choices
  • Infrared Photography Guide
  • Infrared DIY Tutorials

Company

  • Why Choose Us
  • Get In Contact
  • Job Openings
  • Write For Us
  • Affiliate Program
  • Terms of Use
  • Privacy Policy
  • Home
  • Start Here
  • Galleries
  • Tutorials
  • FAQ
  • Blog
  • Why Choose LifePixel?
  • Shop
  • Contact

Copyright © 2023 Life Pixel Infrared - All rights reserved - LifePixel Infrared Photography IR Conversion, Modification & Scratched Sensor Repair