Page Type: Customer Story

TIRF MicroscopyCustomer Stories

Dr. Shiaulou Yuan

Postdoctoral Associate in Pediatrics (Cardiology)
Yale University

Background

The Martina Brueckner lab at Yale University School of Medicine studies the genes of children with congenital heart disease. “We take a human genetics approach combined with animal models, such as mouse and zebrafish, and in vivo imaging. In particular, we do a lot of live imaging of cilia, hair-like structures on the cell surface that function as cellular antennas,” Shiaulou Yuan, a postdoctoral researcher explained. “The cilium is a tiny organelle that is packed with hundreds of distinct signaling molecules. We know these must be important because mutations in genes that are important for cilia biogenesis or signaling can cause congenital heart disease. The challenge is that for many of these genes, we simply don’t know how they can cause congenital heart disease. To understand how these genes are functioning requires us to create a whole-animal, as well as apply high-resolution live imaging approaches, that are guided by human genetics. It’s exciting because it’s the type of science that can only be done nowadays rather than twenty years ago, because of the remarkable advances in genomic and imaging technologies. It all comes together to enable us to understand the problem from new angles.”

TIRF Microscopy
A live image of a cilium from a mouse cell expressing a genetically encoded calcium biosensor (green) and a membrane localized fluorophore (red).
Recording by Shiaulou Yuan and Mohammed Mahamdeh using a Zeiss 63X 1.2NA water immersion objective.

Challenge

Image collection for Dr. Yuan relies not only on sensitivity and resolution, but also fast speeds. “Much of work depends on genetically encoded biosensors or GFP-knock-ins, which are endogenously tagged with a single copy of GFP. They are not that bright, but at the same time, we are also doing live imaging of mouse or zebrafish embryos that require rapid image acquisitions over several hours as the animals happily develop. We have a limited photon budget, yet we must capture a lot of images very rapidly and over a long period of time. We also need high resolution because we’re looking at tiny cilia, but also speed, because they move very fast. Finally, on top of all this, we must keep the laser excitation power low because the animal has to stay alive during all of this – the imaging needs to be gentle.”

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

“The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B is truly transformative for our type of work. Besides the sensitivity, the combination of speed and resolution of the Prime 95B, which is superior to an EMCCD, makes it killer for our experiments. In fact, we have been limited in the past due to insufficient camera technologies. With the Prime 95B on hand, we are now able to attack these questions.”

Live Cell Fluorescence MicroscopyCustomer Stories

Christof Osman, PhD, Professor

Ludwig-Maximilian University, München, Germany
Department of Biology II, Faculty of Biology, Cell and Developmental Biology

Background

The lab of Prof. Osman’s at the Ludwig-Maximilian University in München, Germany is interested in understanding the power plants of cells – mitochondria – and the way their functionality and network activity is maintained during cell division. The underlying process of ensuring that the mitochondrial DNA is correctly distributed between cells undergoing cell division so that cells can produce the required proteins, is the lab’s goal. The team developed a tool which allows them to track in yeast mitochondrial DNA, in the least-possible invasive manner, with high-speed live-cell fluorescence microscopy.

Live Cell Imaging
Maximum intensity projection of 45 planes showing live yeast mitochondria labelled with mKate2 and mitochondrial DNA with tandem-mNeonGreen. Image was taken with a Photometrics Prime 95B 25mm CMOS camera on a Nikon Ti2 microscope.

Challenge

The lab’s research organism is yeast, which is notoriously challenging to image as samples are small and low in fluorescence. Moreover, as the process of cell division and the function of mitochondria is very sensitive to exposure with light (in particular with wavelength in the UV and blue end of the spectrum), the research team would like to use a light dose, as low as possible, for excitation. This allows them the ability to image samples under physiological conditions. Additionally, the events to be observed can be relatively rare, and therefore it is important to image as many cells as possible in one attempt to achieve optimal statistics.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

Prof. Osman is using two Prime 95B 25mm Scientific CMOS cameras with a new TwinCam which is suited for the 25mm diameter light path of the Nikon Ti2 microscope. “The Prime 95B camera provides the required sensitivity that is needed to image our yeast cells with as little excitation light as possible. This prevents phototoxic effects and allows us to maintain cells under physiological conditions throughout long imaging experiments,“ Prof. Osman shares. The TwinCam allows the ability to image two channels simultaneously without having the need to switch filters in-between which leads to losing temporal resolution.

Single Molecule ImagingCustomer Stories

Prof. Mark Leake

Professor Anniversary Chair of Biological Physics
University of York

Background

Prof. Leake founded and leads the Biological Physical Sciences Institute at the University of York, which brings together scientists researching the biomolecular interactions, biological modelling imaging and quantitation of complex data. His work targets a broad range of fundamental processes and open questions in biology, and has provided insight into topics such as the behavioural mechanics of the flagellar motor of bacteria, protein transport, DNA replication, repair and remodelling, signal transduction, gene regulation and oxidiative phosphorylation.

Live yeast cells displaying GFP labeled Mig1, an essential transcription factor, at millisecond sampling and single-molecule sensitivity.

Challenge

Prof. Leake’s lab is at the forefront of developing new biophysical instrumentation to probe cells and biological specimens on a single-molecule level. Single-molecule imaging is a hugely powerful cutting-edge technique for examining fundamental processes and interactions in biological systems. However, the technique is also among the most demanding low-light imaging applications, as the fluorescent response from a single fluorophore is very low, and photobleaching must be avoided. Determining the precise quantity and localisation of single-molecule signals requires an excellent signal to noise ratio for the weakest of signals, while simultaneously delivering high spatial and temporal resolution.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

The Prime 95B Scientific CMOS camera uses back illumination to reach near-perfect quantum efficiency, which combined with low readout noise and large pixels, provides the sensitivity required for single-molecule fluorescence. “The Prime 95B combines the speed of a CMOS camera with sensitivity at or better than an EMCCD, allowing us to push single-molecule microscopy into larger specimens, imaging even faster phenomena than before,” Prof. Leake tells us.

“The camera is extremely easy to set up, with very few settings so you can get straight to imaging. It even includes its own programmable logic outputs which allow the 95B to control and synchronise with other components on the microscope. Altogether, there is no better camera for cutting-edge single-molecule microscopy than the Prime 95B Scientific CMOS.”

Fluorescence Correlation SpectroscopyCustomer Stories

Prof. Enrico Gratton

Founder and Principle Investigator
Laboratory of Fluorescence Dynamics, University of California, Irvine

Background

The lab of Prof. Enrico Gratton at the University of California, Irvine, is interested in the dynamics of the cell interior. The group investigates this using microscopy combined with mathematical approaches such as fluorescence correlation spectroscopy. As the founder and Principle Investigator of the Laboratory of Fluorescence Dynamics, Prof. Gratton’s team has developed numerous fluorescence-based methods to measure diverse cell properties. This includes measurement of the absolute concentrations of molecules within cellular compartments, detection of aggregation of proteins and the detection of barriers to diffusion. Prof. Gratton also developed Globals for Images, a set of software packages to perform this analysis.

Arabidopsis in agar expressing GFP, imaged using SPIM with the Prime 95B uncorrected for camera noise. Pair correlation function showing obstacles to diffusion due to the cell walls in regions of strong anisotropic motion.
The parallel lines of signal clearly define the boundaries of diffusion at each side of the cell walls. Unlike super-resolution microscopy or other methods, fluctuation correlation spectroscopy images the diffusion itself, rather than the cellular structures which are often not visible.
Time series of 2100 frames over 10.5s, 256×256 pixels, 140nm effective pixel size.

Challenge

To reliably detect the incredibly small fluctuations in image signal required for fluorescence correlation spectroscopy – on the order of 10 electrons of signal – stable and predictable noise characteristics are necessary. Noise is an inherent feature of camera sensors and is corrected to reveal fluorescent fluctuations which are detected and measured. Typical experiments using EMCCD cameras require the noise characteristics, including correlated noise and light-independent pixel variance, to be mapped before every experiment to account for instability in the camera noise over time. After fast, time series fluorescence imaging, the previously mapped noise is removed to detect the variance due to fluorescent fluctuations in each pixel, and allowed mathematical analysis of the signal. With fluctuations in signal being less than 10 electrons in amplitude, high camera sensitivity and being able to accurately correct for the noise are crucial in providing the necessary signal to noise for this analysis.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

Prof. Gratton now uses the Prime 95B back illuminated Scientific CMOS (sCMOS) camera, to take advantage of the stable noise and uncorrelated pixel noise properties. Light-independent pixel noise characteristics are stable over time which means the camera only requires calibration and mapping once, rather than before every experiment.

Prof. Gratton shared, “I didn’t need to account for camera noise in the analyses, unlike when using EMCCDs and other CMOS cameras, which suffer from unstable noise. The reliability and stability of the pixel noise, makes the Prime 95B Scientific CMOS camera an ideal imaging solution for fluorescence correlation spectroscopy methods.” Having predictable and easily modelled pixel to pixel variation produces the highest signal to noise ratio and results in detection of smaller fluctuations than possible when using an EMCCD.

Single Molecule BiophysicsCustomer Stories

Dr. Christoph Baumann, Lecturer in Molecular Biophysics

Department of Biology, University of York

Background

Dr. Christoph Baumann, Lecturer at the University of York, Department of Biology and his group work with advanced imaging techniques to push forward our understanding of spatio-temporal dynamics in the bacterial cell envelope. Using a Photometrics camera, the group was the first to observe that, contrary to expectations, proteins in the outer cell membrane don’t diffuse significantly when tracked, and that new proteins are inserted predominantly at mid-cell during growth.1 This means that bacteria can very quickly turnover their outer membrane proteins to adapt to new environmental challenges during growth, and this work initiated a new investigation of inter-membrane crosstalk in the Gram negative bacterial cell envelope.

Figure 1: Alexa Fluor 488-labeled colicin E9 protein molecules bound to extracellular face of BtuB transmembrane receptors in the outer membrane of live Escherichia coli JM83 cells (256 x 256 pixels, 16.9 x 16.9 µm, 30 frame sum, video data collected with 33 ms exposure and global shuttering).

Challenge

To pursue this research area, Dr. Baumann and his colleagues use TIRF microscopy alongside laser scanning confocal FRAP microscopy. When tracking single molecules, sensitivity and speed are all-important. “Better temporal and spatial resolution means better quality data,” Dr. Baumann shares. Previously, the large pixels, slow speed, and the excess noise factor of their EMCCD camera limited both these aspects. Further, the small sensor size and the need to use a 1.6× magnification optic to match pixel size lead to a very small field of view, and using additional lenses lost them precious light.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

The Photometrics Prime 95B Scientific CMOS (sCMOS) camera was the perfect fit for the team’s research, with the 11 µm pixels giving optimal resolution paired with the 100× objectives used for TIRF microscopy. The faster speed and higher signal to noise ratio of the back-illuminated CMOS also provided better temporal resolution. “This increased resolution is of great benefit for all the research we do, not just this experiment,” Dr. Baumann told us. “Since the camera is USB3.0, it’s very easy to move the camera to other setups for short periods.”

The huge field of view of the Prime 95B is not only useful for increasing throughput, but allows the team to use single-camera optical splitting technology. Dr. Baumann concluded, “We’re going to use a polarization splitter in an upcoming experiment, and the Prime 95B’s chip is large enough to still have a great field of view with both images side by side.”

References

  1. Supramolecular assemblies underpin turnover of outer membrane proteins in bacteria, P. Rassam et al., 2015, Nature 523: 333-336.
  2. Intermembrane crosstalk drives inner-membrane protein organization in Escherichia coli, P. Rassam et al., 2018, Nature Commun 9: 1082.

Single-Molecule BiophysicsCustomer Stories

Dr. Kevin Freedman, Assistant Professor, Bioengineering,

University of California Riverside, Department of Bioengineering

Background

The Freedman Lab studies single molecule biophysics using a variety of electrical and optical signal measurements. Most notably, the lab studies complex biological systems where molecular populations are heterogeneous and difficult to study using ensemble averaging. Whenever working with single molecules, sensitivity is a big challenge. As a lab which focuses on single molecule detection, they require high end imaging equipment. This is not only for high sensitivity but also for high temporal resolution (i.e. fast frame rates). In some cases, fluorescent nanoscale beads are used to characterize the devices custom-fabricated in the lab so the need for fast sampling is a limiting factor.

Maximum intensity projection of electrically charged beads moving through an electric field over time. Electrically charged ports on the left and right hand side of the image cause particles to move at high velocity through the pore. The tracks that can be seen show the movement of the beads.

Challenge

The Freedman Lab designs and characterizes nanofluidic devices that are used for biophysical or device physics (i.e. bead tracking) experiments. Often times, using the devices, nano-beads are transported at high velocities between two fabricated structures where speeds of up to 1000 fps are necessary to track them accurately.

To achieve this high frame rate, the exposure time needs to be 1 ms. This means the camera must be capable of reaching this high frame rate as well as being sensitive enough to detect the nano-beads with such a low exposure time. This isn’t possible with the lower speed of an EMCCD camera, and front-illuminated sCMOS cameras lack the sensitivity.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

The Freedman Lab now uses the back-illuminated Prime 95B Scientific CMOS camera for their single molecule imaging experiments.

With 95% quantum efficiency, the Prime 95B has the sensitivity to detect particles with the 1 ms exposure time used in their challenging nano-bead velocimetry experiments. Also, with the increased speed afforded by CMOS technology, the Prime 95B can easily reach the desired 1000 fps frame rate. This allows accurate bead tracking in a range of experimental parameters which were not accessible before.

Dr. Freedman told us, “We’ve been using the Prime 95B as one of our main cameras for both single molecule sensing and nano-bead velocity measurements. The Prime 95B Scientific CMOS is excellent for low-noise, high-sensitivity, and fast measurements.”

Single Molecule Tracking PALMCustomer Stories

Prof. Thomas Etheridge

Antony Carr Group, Genome Damage and Stability Centre, University of Sussex

Background

The Carr Lab at the Genome Damage and Stability Centre, University of Sussex, investigates DNA metabolism processes such as DNA replication and repair. They are interested in the challenges cells face during DNA replication and the cellular processes that help the cell overcome replication fork stalling or collapse. To study this, they focus on the behaviors and interactions of individual proteins involved in DNA replication in both fission yeast and human cells.

Human cell nucleus with DNA repair complex labelled with HaloTag-PA-JF549. Scale bar: 5µm.
Left: Superimposed tracks of detected molecules. Red = DNA-bound, static molecule. Cyan = freely diffusing complexes.
Right: Localization map of complexes. Hot spots indicating locations of DNA bound molecules.

Challenge

One approach used to examine the DNA association of proteins is to break open the cell, extract the proteins and perform western blotting. However, this approach reveals nothing of the dynamics of association, and destroys cells in the process.

A more demanding alternative is to use an imaging technique capable of single protein resolution. To this end, Dr. Etheridge uses Single Molecule Tracking PALM to observe the association of proteins with the DNA in real time, non-invasively, in both yeast cells and human cells. Single fluorescent molecules move quickly and give off very little light so this technique requires high speed and the highest sensitivity.

The fluorescent proteins used in the yeast cells are very dim and, until now, Dr. Etheridge has been using an EMCCD camera to observe them. However, the field of view given by his EMCCD camera is quite small. For human cells, brighter synthetic dyes can be used so dynamics can be observed with better temporal resolution. Unfortunately, the lower speed of his EMCCD camera doesn’t allow for this.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

The back illuminated Prime 95B scientific CMOS camera has the speed and field of view advantages expected of CMOS cameras, but with the sensitivity to rival or beat EMCCDs. This gives researchers using single molecule techniques unprecedented low-light detection and temporal resolution.

Dr. Etheridge shared, “To image the demanding yeast cells with our EMCCD, we were having to do multiple experiments on different areas of the sample to generate enough data for it to be worth processing. With the field of view of the Prime 95B, we can gather enough cells in the field of view to process in a single shot. In the human cell system, using the brighter dyes, we can image our favorite proteins at much faster speeds.”

High-Speed FRETCustomer Stories

Professor Andrew Plested

Leibniz Research Institute for Molecular Pharmacology, Humboldt University Berlin

Background

The Plested lab investigates the characterization of receptors relevant to neuronal systems. They apply multiple techniques to image isolated neurons, including a combination of electrophysiology and fluorescence live-cell imaging.

One of their areas of study involves measuring Foerster Resonance Energy Transfer (FRET) upon electrical stimulation of the neurons. They label individual relevant structures and receptors with suitable fluorophores and observe the FRET signal in the dendritic region of cells of interest. This enables them to obtain information about the state, localization, and behavior of channels, and particularly their colocalization in the nanometer range.

Figure 1. Left Hippocampal neuronal culture expressing receptor and scaffold protein tagged with GFP and mScarlet, respectively. Maximum intensity projection from both fluorophores combined. 488 and 561 nm excitation, Optosplit 550 nm dichroic, images aligned in Cairn Research ImageJ plugin.
Right Average FRET signal (8-bit, max 255) from 10 frames (100 ms total exposure). Maximum projection was thresholded and used to mask FRET calculation, restricting to cell processes. FRET calculation was done in IGOR Pro. Image manipulation in ImageJ.

Challenge

The individual interactions the group is interested in observing only last for a very brief period of time (10-100 ms). Therefore, to capture the weak signal arising from the energy transfer from a donor fluorophore to an acceptor molecule, very fast imaging is required. This means the number of photons available for detection is very limited and an extremely sensitive imaging device is essential.

Their currently used EMCCD camera – although sensitive enough for detection – is only able to image a very small field of view which makes experimental measurements a time-consuming exercise. FRET measurements are also limited by the 30 ms read time per frame of the EMCCD camera, achieving just 30 fps (corresponding to ~15 fps FRET) at full field. Furthermore, binning had to be used to increase frame rate, reducing spatial resolution.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

The Prime 95B Scientific CMOS camera delivers three critical advantages to Dr. Plested’s experiments: Sensitivity, field of view (FOV) and speed.

First, the relevant power of excitation can be reduced by a factor of 5 – giving a more physiologically-relevant measurement and also reducing artifacts caused by bleaching.

Second, the larger sensor of the Prime 95B resulted in about five times the field of view, dramatically increasing the throughput of cellular regions per experiment.

And finally, along with the larger field of view, the frame rate can also be increased. By imaging at 50 fps (effective FRET measurement at 25 fps, with alternating excitation, see Figure 1) the data is much more relevant to synaptic transmission (timescale of interest 10-100 ms). This means that their measurements are now limited by probe properties, not the camera.

The Prime 95B gave the Plested lab an improved way to obtain their data, switching from essentially single object imaging to a multiple neurite view, yielding more detailed insight into synaptic transmission.

NanophotonicsCustomer Stories

Dr. Mathieu Mivelle

Research Fellow, Sorbonne University

Background

Dr. Mivelle’s research lies within the field of nanophotonics and centers around investigations into the interactions between light and matter on the nanoscale to increase understanding of optical properties.

Dr. Mivelle explains, ‘Most current technologies make use of the electric field component of light, however, my research investigates the interaction of the magnetic optical field component with matter, which is much weaker’.

Dr. Mivelle designs structures that are patterned at the nanoscale, and couples these to single quantum emitters, such as single fluorescent molecules or lanthanide doped nanocrystals to produce physical effects between the two that are not found in nature. This spatial coupling permits Dr. Mivelle to modify the quantum properties of the emitters which could provide new opportunities in photonics for technological applications.

Figure 1. Quantum emitters imaged using the Prime 95B sCMOS camera on the custom-built microscope setup.

Challenge

Dr. Mivelle uses a custom set up that consists of an inverted microscope, on top of which is a near field scanning probe, not unlike those used in AFM, but with the nanopatterned structure attached.

The nanostructure is brought into close proximity (~10 nm) to the sample consisting of nanocrystals, 50 nm in diameter, doped with rare earth lanthanide ions, such as erbium and europium, which are used in many technologies. Lanthanides are known to be very dim emitters in terms of photon counts, Dr. Mivelle explained, ‘I require a very sensitive camera to be able to locate these single emitters during sample scanning at speed’.

In order to couple the nanostructure to the single emitters, Dr. Mivelle must first locate them in the sample during scanning over tens of milliseconds, which provides a challenge in terms of speed and sensitivity.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

Dr. Mivelle is using the Prime 95B in his custom-built setup to identify these single emitters during sample scanning at high speeds. He told us, ‘The combination of the high SNR and quantum efficiency [of the Prime 95B] allows me to see the very dim signals emitted from the lanthanide doped particles.’ He continued, ‘We picked the Prime 95B based on the speed and the sensitivity, which was equivalent to EMCCDs but at a much better value for money. We compared with other EMCCD technologies and, for our application, the Prime 95B was the best.’

Although field of view (FOV) is not currently the issue, Dr Mivelle anticipates that the increased FOV of the Prime 95B will provide benefits for future super-resolution localization (STORM) experiments.

Calcium ImagingCustomer Stories

Professor Colin Brownlee, Marine Biological Association

Plymouth Director 2007-2017, Marine Biological Association Chair of Marine Biosciences, University of Southampton

Background

Phytoplankton play a critical role in Earth’s carbon and nutrient cycles, and in the regulation of our climate, yet are relatively poorly understood. The Brownlee Group at the Marine Biological Association study various processes that occur in living phytoplankton ranging from interactions between large populations of organisms to processes within single cells. Conventional microscopes and objectives are incapable of studying large enough populations of cells with sufficient resolution to discern sub-cellular details. The group therefore use the Mesolens system, a 4× objective with nearly 0.5NA, which can provide highly detailed images for a field of view 5mm across. The Mesolens, developed by Brad Amos and Gail McConnell at the University of Strathclyde, uses precision-made lenses to minimize spherical and chromatic aberration across the huge field of view.

Diatoms expressing R-GECO without stimulation (5 second exposure, background subtracted).

Challenge

The group are using calcium imaging to study dynamic behaviour in large populations of diatoms and coccolithophores expressing R-GECO, and need to preserve sub-cellular details and structures. A conventional CMOS camera wouldn’t have the field of view and resolution to take advantage of the Mesolens, so a moving-array CCD was previously used – however this camera was incapable of the sensitivity and speed required for calcium imaging.

The quantum efficiency of the camera is a really important factor for us. If we can use less excitation power, we can increase the length of our imaging and minimize photodamage to the animal. The sensitivity of the Prime 95B [Scientific CMOS camera] is truly transformative for our type of work.

Solution

The Photometrics Iris 15 Scientific CMOS (sCMOS) camera, with its 25mm field of view and 4.25µm pixels uniquely provides the field of view, resolution, sensitivity and speed for such detailed studies of large populations of cells. “One image shows us around a thousand cells,” says Professor Brownlee, Chair of Marine Biosciences, University of South Hampton. “We can capture a usable image with a 200ms exposure time on the Iris 15. The minimum exposure for a similar image from our previous camera was over a second – and then the camera would take two seconds to read the image out!”